Location: Lovell, Cloherty, Celler, Dokos, 2004 @ 0b0b899b03f4 / lovell_cloherty_celler_dokos_2004.cellml

Author:
pmr2.import <nobody@models.cellml.org>
Date:
2009-06-17 15:02:54+12:00
Desc:
committing version01 of lovell_cloherty_celler_dokos_2004
Permanent Source URI:
https://models.physiomeproject.org/workspace/lovell_cloherty_celler_dokos_2004/rawfile/0b0b899b03f47402b2f30f30ba868fa23abab1e5/lovell_cloherty_celler_dokos_2004.cellml

<?xml version='1.0' encoding='utf-8'?>
<!-- FILE : Lovell_model_2004.xml

CREATED : 24th April 2004

LAST MODIFIED : 27th April 2005

AUTHOR : Catherine Lloyd
         Bioengineering Instute
         The University of Auckland
         
MODEL STATUS : This model conforms to the CellML 1.0 Specification released on
10th August 2001, and the 16/01/2002 CellML Metadata 1.0 Specification.

DESCRIPTION : This file contains a CellML description of Lovell et al.'s 2004 mathematical model of cardiac pacemaker myocytes.

CHANGES: 
   27/04/2005 - PJV - Made MathML id's unique. Removed undefined
                      initial values.
  
--><model xmlns="http://www.cellml.org/cellml/1.0#" xmlns:cmeta="http://www.cellml.org/metadata/1.0#" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:bqs="http://www.cellml.org/bqs/1.0#" xmlns:cellml="http://www.cellml.org/cellml/1.0#" xmlns:dcterms="http://purl.org/dc/terms/" xmlns:vCard="http://www.w3.org/2001/vcard-rdf/3.0#" cmeta:id="lovell_cloherty_celler_dokos_2004_version01" name="lovell_cloherty_celler_dokos_2004_version01">
<documentation xmlns="http://cellml.org/tmp-documentation">
<article>
  <articleinfo>
  <title>A Gradient Model Of Cardiac Pacemaker Myocytes</title>
  <author>
    <firstname>Catherine</firstname>
          <surname>Lloyd</surname>
    <affiliation>
      <shortaffil>Bioengineering Institute, University of Auckland</shortaffil>
    </affiliation>
  </author>
</articleinfo>
  <section id="sec_status">
    <title>Model Status</title>
    <para>
            This model is currently non-functional.
          </para>
  </section>
  <sect1 id="sec_structure">
<title>Model Structure</title>

<para>
Electrical activity of the healthy mammalian heart is initiated by an area of specialised pacemaker cells in the wall of the heart, known as the sinoatrial node (SAN).  These cells are spontaneously active, demonstrating a slow depolarisation to threshold (pacemaker potential) rather than a stable resting potential.  Despite heterogeneity amongst the cells of the SAN, the cells are able to synchronise their firing rate and this in turn stimulates the contraction of the atrial myocardium.  Synchronisation is achieved by electronic coupling between cells via gap junctions.
</para>

<para>
To date, two potential theories have been put forward to explain the observed spatial heterogeneity in the action potential characteristics within the SAN:
</para>
<itemizedlist>
  <listitem>
            <para>1) The gradient model suggests that the heterogeneity arises intrinsically from a spatial gradient in underlying cellular electrophysiological properties; and </para>
          </listitem>
  <listitem>
            <para>2) The mosaic model, which suggests that atrial myocytes are peppered throughout the SAN region, increasing in density towards the periphery.  Action potential heterogeneity then arises due to the electronic coupling between atrial and pacemaker myocytes, and the differences between the relative density of the two cell types with the SAN.</para>
          </listitem>
</itemizedlist>

<para>
In order to further investigate the source of the action potential heterogeneity in the SAN, a mathematical model has been devloped by Lovell <emphasis>et al</emphasis>. (see the figure below).  Several mathematical models of the SAN activity have been previously published, including:
</para>
<itemizedlist>
  <listitem>
            <para>
              Demir <emphasis>et al.</emphasis> Sinoatrial Node Model, 1994;
            </para>
          </listitem>
  <listitem>
            <para>
              Modelling the Ion Currents Underlying Sinoatrial Node Pacemaker Activity, Dokos <emphasis>et al.</emphasis>, 1996;
            </para>
          </listitem>
  <listitem>
            <para>
              A Model of Sinoatrial Node Vagal Control, Dokos <emphasis>et al.</emphasis>, 1996;
            </para>
          </listitem>
  <listitem>
            <para>
              Demir <emphasis>et al.</emphasis> Sinoatrial Node Model, 1999;
            </para>
          </listitem>
  <listitem>
            <para>
              Zhang <emphasis>et al.</emphasis> Sinoatrial Node Model, 2000;
            </para>
          </listitem>
  <listitem>
            <para>
              Boyett <emphasis>et al.</emphasis> Sinoatrial Node Model, 2001;
            </para>
          </listitem> and 
  <listitem>
            <para>
              Kurata <emphasis>et al.</emphasis> Improved Mathematical Model for the Primary Pacemaker Cell, 2002.
            </para>
          </listitem>
</itemizedlist>
<para>
Although these models were able to recreate the generic action potential waveforms from the SAN, none were able to represent action potential waveforms from any specific SAN cell.  This limits the application of such models to analyse the factors underlying action potential heterogeneity in coupled systems of pacemaker cells, as well as elucidating specific ionic mechanisms underlying action potential heterogeneity in the SAN.
</para>

<para>
To meet these needs, Lovell <emphasis>et al.</emphasis> have devloped a generic single cell ionic model of rabbit SAN cells, which is based on Markovian state kinetics (all previously published SAN models are based on a Hodgkin-Huxley mechanism).  Parameters are fitted to this model using a custom least squares optimisation approach.  They then propose a gradient model of the SAN by employing the same optimisation approach to fit a smooth transition in ionic model parameters to achieve a desired variation in AP characteristics.
</para>

<para>
The model has been described here in CellML.  It should be noted that the initial parameters entered into this model are those for the central SAN value.  Peripheral SAN values and the interpolation parameters are also provided in the original publication.    
</para>

<para>
The complete original paper reference is cited below:
</para>

<para>
<ulink url="http://linkinghub.elsevier.com/retrieve/pii/S0079610703001123">
            <emphasis>Progress in Biophysics and Molecular Biology</emphasis>
          </ulink>, 85, 301-323.  (<ulink url="http://www.sciencedirect.com/science/journal/00796107">Full text (HTML)</ulink> and PDF versions of the article are available to subscribers on the <emphasis>Progress in Biophysics and Molecular Biology</emphasis> website.)  <ulink url="http://www.ncbi.nlm.nih.gov/pubmed/15142749">PubMed ID: 15142749</ulink> 
</para>

<informalfigure float="0" id="fig_cell_diagram">
          <mediaobject>
            <imageobject>
              <objectinfo>
                <title>cell diagram</title>
              </objectinfo>
              <imagedata fileref="lovell_2004.png"/>
            </imageobject>
            <caption>
A schematic diagram describing the ionic components of the SA node mathematical model.    
</caption>
          </mediaobject>
        </informalfigure>

</sect1>
</article>
</documentation>
  
  
  
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  <component name="T_type_calcium_current">
    <variable units="picoA" public_interface="out" name="i_CaT"/>

    <variable units="nanoS" name="g_CaT" initial_value="6.816E2"/>
    <variable units="dimensionless" name="A_CaT" initial_value="1.562E-5"/>
    <variable units="dimensionless" name="I1" initial_value="9.985E-1"/>
    <variable units="dimensionless" name="I2"/>
    <variable units="first_order_rate_constant" name="alpha1"/>
    <variable units="first_order_rate_constant" name="alpha2"/>
    <variable units="first_order_rate_constant" name="alpha3"/>
    <variable units="first_order_rate_constant" name="beta1"/>
    <variable units="first_order_rate_constant" name="beta3"/>
    <variable units="first_order_rate_constant" name="alpha1_0" initial_value="0.0"/>
    <variable units="first_order_rate_constant" name="alpha1_infinity" initial_value="1.203E3"/>
    <variable units="millivolt" name="alpha1_E50" initial_value="-3.442E1"/>
    <variable units="millivolt" name="alpha1_Eslope" initial_value="6.143"/>
    <variable units="first_order_rate_constant" name="alpha2_0" initial_value="2.458E2"/>
    <variable units="first_order_rate_constant" name="alpha2_infinity" initial_value="1.304E3"/>
    <variable units="millivolt" name="alpha2_E50" initial_value="-1.978E1"/>
    <variable units="millivolt" name="alpha2_Eslope" initial_value="1.260E1"/>
    <variable units="first_order_rate_constant" name="alpha3_0" initial_value="1.003E-1"/>
    <variable units="first_order_rate_constant" name="alpha3_infinity" initial_value="1.157E-2"/>
    <variable units="millivolt" name="alpha3_E50" initial_value="6.079"/>
    <variable units="millivolt" name="alpha3_Eslope" initial_value="4.938E-1"/>
    <variable units="first_order_rate_constant" name="beta1_0" initial_value="8.075E2"/>
    <variable units="first_order_rate_constant" name="beta1_infinity" initial_value="9.663"/>
    <variable units="millivolt" name="beta1_E50" initial_value="-3.025E1"/>
    <variable units="millivolt" name="beta1_Eslope" initial_value="2.580E1"/>
    <variable units="first_order_rate_constant" name="beta3_0" initial_value="1.914"/>
    <variable units="first_order_rate_constant" name="beta3_infinity" initial_value="4.490E2"/>
    <variable units="millivolt" name="beta3_E50" initial_value="-3.948E1"/>
    <variable units="millivolt" name="beta3_Eslope" initial_value="1.295E1"/>
    
    <variable units="millivolt" public_interface="in" name="E_Ca_rev"/>
    <variable units="second" public_interface="in" name="time"/>
    <variable units="millivolt" public_interface="in" name="Em"/>
    
    <math xmlns="http://www.w3.org/1998/Math/MathML">
      <apply id="i_CaT_calculation">
        <eq/>
        <ci> i_CaT </ci>
        <apply>
          <times/>
          <ci> g_CaT </ci>
          <ci> A_CaT </ci>
          <apply>
            <minus/>
            <ci> Em </ci>
            <ci> E_Ca_rev </ci>
          </apply>
        </apply>
      </apply>
      
      <apply id="dA_CaT_dt">
        <eq/>
        <apply>
          <diff/>
          <bvar>
            <ci> time </ci>
          </bvar>
          <ci> A_CaT </ci>
        </apply>
        <apply>
          <minus/>
          <apply>
            <times/>
            <ci> alpha1 </ci>
            <ci> I2 </ci>
          </apply>
          <apply>
            <times/>
            <apply>
              <plus/>
              <ci> beta1 </ci>
              <ci> alpha2 </ci>
            </apply>
            <ci> A_CaT </ci>
          </apply>
        </apply>
      </apply>
      
      <apply id="T_type_calcium_current_dI1_dt">
        <eq/>
        <apply>
          <diff/>
          <bvar>
            <ci> time </ci>
          </bvar>
          <ci> I1 </ci>
        </apply>
        <apply>
          <minus/>
          <apply>
            <plus/>
            <apply>
              <times/>
              <ci> alpha2 </ci>
              <ci> A_CaT </ci>
            </apply>
            <apply>
              <times/>
              <ci> beta3 </ci>
              <ci> I2 </ci>
            </apply>
          </apply>
          <apply>
            <times/>
            <ci> alpha3 </ci>
            <ci> I1 </ci>
          </apply>
        </apply>
      </apply>
      
      <apply id="T_type_calcium_current_dI2_dt">
        <eq/>
        <apply>
          <diff/>
          <bvar>
            <ci> time </ci>
          </bvar>
          <ci> I2 </ci>
        </apply>
        <apply>
          <minus/>
          <apply>
            <plus/>
            <apply>
              <times/>
              <ci> alpha3 </ci>
              <ci> I1 </ci>
            </apply>
            <apply>
              <times/>
              <ci> beta1 </ci>
              <ci> A_CaT </ci>
            </apply>
          </apply>
          <apply>
            <times/>
            <apply>
              <plus/>
              <ci> beta3 </ci>
              <ci> alpha1 </ci>
            </apply>
            <ci> I2 </ci>
          </apply>
        </apply>
      </apply>
      
      <apply id="T_type_calcium_current_alpha1_calculation">
        <eq/>
        <ci> alpha1 </ci>
        <apply>
          <plus/>
          <ci> alpha1_infinity </ci>
          <apply>
            <divide/>
            <apply>
              <minus/>
              <ci> alpha1_0 </ci>
              <ci> alpha1_infinity </ci>
            </apply>
            <apply>
              <plus/>
              <cn cellml:units="dimensionless"> 1.0 </cn>
              <apply>
                <exp/>
                <apply>
                  <divide/>
                  <apply>
                    <minus/>
                    <ci> Em </ci>
                    <ci> alpha1_E50 </ci>
                  </apply> 
                  <ci> alpha1_Eslope </ci>
                </apply>
              </apply>
            </apply>
          </apply>
        </apply>
      </apply>
      
      <apply id="T_type_calcium_current_beta1_calculation">
        <eq/>
        <ci> beta1 </ci>
        <apply>
          <plus/>
          <ci> beta1_infinity </ci>
          <apply>
            <divide/>
            <apply>
              <minus/>
              <ci> beta1_0 </ci>
              <ci> beta1_infinity </ci>
            </apply>
            <apply>
              <plus/>
              <cn cellml:units="dimensionless"> 1.0 </cn>
              <apply>
                <exp/>
                <apply>
                  <divide/>
                  <apply>
                    <minus/>
                    <ci> Em </ci>
                    <ci> beta1_E50 </ci>
                  </apply> 
                  <ci> beta1_Eslope </ci>
                </apply>
              </apply>
            </apply>
          </apply>
        </apply>
      </apply>
      
      <apply id="T_type_calcium_current_alpha2_calculation">
        <eq/>
        <ci> alpha2 </ci>
        <apply>
          <plus/>
          <ci> alpha2_infinity </ci>
          <apply>
            <divide/>
            <apply>
              <minus/>
              <ci> alpha2_0 </ci>
              <ci> alpha2_infinity </ci>
            </apply>
            <apply>
              <plus/>
              <cn cellml:units="dimensionless"> 1.0 </cn>
              <apply>
                <exp/>
                <apply>
                  <divide/>
                  <apply>
                    <minus/>
                    <ci> Em </ci>
                    <ci> alpha2_E50 </ci>
                  </apply> 
                  <ci> alpha2_Eslope </ci>
                </apply>
              </apply>
            </apply>
          </apply>
        </apply>
      </apply>
      
      <apply id="T_type_calcium_current_alpha3_calculation">
        <eq/>
        <ci> alpha3 </ci>
        <apply>
          <plus/>
          <ci> alpha3_infinity </ci>
          <apply>
            <divide/>
            <apply>
              <minus/>
              <ci> alpha3_0 </ci>
              <ci> alpha3_infinity </ci>
            </apply>
            <apply>
              <plus/>
              <cn cellml:units="dimensionless"> 1.0 </cn>
              <apply>
                <exp/>
                <apply>
                  <divide/>
                  <apply>
                    <minus/>
                    <ci> Em </ci>
                    <ci> alpha3_E50 </ci>
                  </apply> 
                  <ci> alpha3_Eslope </ci>
                </apply>
              </apply>
            </apply>
          </apply>
        </apply>
      </apply>
      
      <apply id="T_type_calcium_current_beta3_calculation">
        <eq/>
        <ci> beta3 </ci>
        <apply>
          <plus/>
          <ci> beta3_infinity </ci>
          <apply>
            <divide/>
            <apply>
              <minus/>
              <ci> beta3_0 </ci>
              <ci> beta3_infinity </ci>
            </apply>
            <apply>
              <plus/>
              <cn cellml:units="dimensionless"> 1.0 </cn>
              <apply>
                <exp/>
                <apply>
                  <divide/>
                  <apply>
                    <minus/>
                    <ci> Em </ci>
                    <ci> beta3_E50 </ci>
                  </apply> 
                  <ci> beta3_Eslope </ci>
                </apply>
              </apply>
            </apply>
          </apply>
        </apply>
      </apply>
    </math>
  </component>
  
  <component name="rapid_delayed_rectifying_potassium_current">
    <variable units="picoA" public_interface="out" name="i_Kr"/>
    <variable units="picoA" public_interface="out" name="i_Kr_Na"/>
    <variable units="picoA" public_interface="out" name="i_Kr_K"/>
    
    <variable units="nanoS" name="g_Kr" initial_value="4.714"/>
    <variable units="picoA_per_millimolar" name="PKNa_r" initial_value="3.042E-2"/>
    <variable units="dimensionless" name="A_Kr" initial_value="1.209E-1"/>
    <variable units="dimensionless" name="I1" initial_value="1.991E-3"/>
    <variable units="dimensionless" name="I2" initial_value="5.617E-2"/>
    <variable units="dimensionless" name="I3"/>
    <variable units="first_order_rate_constant" name="alpha1"/>
    <variable units="first_order_rate_constant" name="alpha2"/>
    <variable units="first_order_rate_constant" name="alpha3"/>
    <variable units="first_order_rate_constant" name="alpha4"/>
    <variable units="first_order_rate_constant" name="beta1"/>
    <variable units="first_order_rate_constant" name="beta4"/>
    <variable units="first_order_rate_constant" name="alpha1_0" initial_value="2.924E-1"/>
    <variable units="first_order_rate_constant" name="alpha1_infinity" initial_value="1.796"/>
    <variable units="millivolt" name="alpha1_E50" initial_value="-2.821"/>
    <variable units="millivolt" name="alpha1_Eslope" initial_value="1.591E1"/>
    <variable units="first_order_rate_constant" name="alpha2_0" initial_value="8.011E-4"/>
    <variable units="first_order_rate_constant" name="alpha2_infinity" initial_value="2.815E1"/>
    <variable units="millivolt" name="alpha2_E50" initial_value="2.607E1"/>
    <variable units="millivolt" name="alpha2_Eslope" initial_value="4.849"/>
    <variable units="first_order_rate_constant" name="alpha3_0" initial_value="0.0"/>
    <variable units="first_order_rate_constant" name="alpha3_infinity" initial_value="1.382E1"/>
    <variable units="millivolt" name="alpha3_E50" initial_value="-1.706"/>
    <variable units="millivolt" name="alpha3_Eslope" initial_value="8.661"/>
    <variable units="first_order_rate_constant" name="alpha4_0" initial_value="8.526E1"/>
    <variable units="first_order_rate_constant" name="alpha4_infinity" initial_value="5.840"/>
    <variable units="millivolt" name="alpha4_E50" initial_value="1.663E1"/>
    <variable units="millivolt" name="alpha4_Eslope" initial_value="1.906E1"/>
    <variable units="first_order_rate_constant" name="beta1_0" initial_value="1.161E-1"/>
    <variable units="first_order_rate_constant" name="beta1_infinity" initial_value="5.201E1"/>
    <variable units="millivolt" name="beta1_E50" initial_value="-6.477"/>
    <variable units="millivolt" name="beta1_Eslope" initial_value="1.149E1"/>
    <variable units="first_order_rate_constant" name="beta4_0" initial_value="5.728"/>
    <variable units="first_order_rate_constant" name="beta4_infinity" initial_value="5.372E2"/>
    <variable units="millivolt" name="beta4_E50" initial_value="4.594E1"/>
    <variable units="millivolt" name="beta4_Eslope" initial_value="4.646"/>
    
    <variable units="millivolt" public_interface="in" name="E_Na"/>
    <variable units="millivolt" public_interface="in" name="E_K"/>
    <variable units="second" public_interface="in" name="time"/>
    <variable units="millivolt" public_interface="in" name="Em"/>
    
    <math xmlns="http://www.w3.org/1998/Math/MathML">
      <apply id="i_Kr_calculation">
        <eq/>
        <ci> i_Kr </ci>
        <apply>
          <plus/>
          <ci> i_Kr_Na </ci>
          <ci> i_Kr_K </ci>
        </apply>
      </apply>
      
      <apply id="i_Kr_Na_calculation">
        <eq/>
        <ci> i_Kr_Na </ci>
        <apply>
          <times/>
          <ci> g_Kr </ci>
          <ci> A_Kr </ci>
          <ci> PKNa_r </ci>
          <apply>
            <minus/>
            <ci> Em </ci>
            <ci> E_Na </ci>
          </apply>
        </apply>
      </apply>
      
      <apply id="i_Kr_K_calculation">
        <eq/>
        <ci> i_Kr_K </ci>
        <apply>
          <times/>
          <ci> g_Kr </ci>
          <ci> A_Kr </ci>
          <apply>
            <minus/>
            <ci> Em </ci>
            <ci> E_K </ci>
          </apply>
        </apply>
      </apply>
      
      <apply id="dA_Kr_dt">
        <eq/>
        <apply>
          <diff/>
          <bvar>
            <ci> time </ci>
          </bvar>
          <ci> A_Kr </ci>
        </apply>
        <apply>
          <minus/>
          <apply>
            <times/>
            <ci> alpha1 </ci>
            <ci> I3 </ci>
          </apply>
          <apply>
            <times/>
            <apply>
              <plus/>
              <ci> beta1 </ci>
              <ci> alpha2 </ci>
            </apply>
            <ci> A_Kr </ci>
          </apply>
        </apply>
      </apply>
      
      <apply id="rapid_delayed_rectifying_potassium_current_dI1_dt">
        <eq/>
        <apply>
          <diff/>
          <bvar>
            <ci> time </ci>
          </bvar>
          <ci> I1 </ci>
        </apply>
        <apply>
          <minus/>
          <apply>
            <times/>
            <ci> alpha2 </ci>
            <ci> A_Kr </ci>
          </apply>
          <apply>
            <times/>
            <ci> alpha3 </ci>
            <ci> I1 </ci>
          </apply>
        </apply>
      </apply>
      
      <apply id="rapid_delayed_rectifying_potassium_current_dI2_dt">
        <eq/>
        <apply>
          <diff/>
          <bvar>
            <ci> time </ci>
          </bvar>
          <ci> I2 </ci>
        </apply>
        <apply>
          <minus/>
          <apply>
            <plus/>
            <apply>
              <times/>
              <ci> alpha3 </ci>
              <ci> I1 </ci>
            </apply>
            <apply>
              <times/>
              <ci> beta4 </ci>
              <ci> I3 </ci>
            </apply>
          </apply>
          <apply>
            <times/>
            <ci> alpha4 </ci>
            <ci> I2 </ci>
          </apply>
        </apply>
      </apply>
      
      <apply id="rapid_delayed_rectifying_potassium_current_dI3_dt">
        <eq/>
        <apply>
          <diff/>
          <bvar>
            <ci> time </ci>
          </bvar>
          <ci> I3 </ci>
        </apply>
        <apply>
          <minus/>
          <apply>
            <plus/>
            <apply>
              <times/>
              <ci> beta1 </ci>
              <ci> A_Kr </ci>
            </apply>
            <apply>
              <times/>
              <ci> alpha4 </ci>
              <ci> I2 </ci>
            </apply>
          </apply>
          <apply>
            <times/>
            <apply>
              <plus/>
              <ci> alpha1 </ci>
              <ci> beta4 </ci>
            </apply>
            <ci> I3 </ci>
          </apply>
        </apply>
      </apply>
      
      <apply id="rapid_delayed_rectifying_potassium_current_alpha1_calculation">
        <eq/>
        <ci> alpha1 </ci>
        <apply>
          <plus/>
          <ci> alpha1_infinity </ci>
          <apply>
            <divide/>
            <apply>
              <minus/>
              <ci> alpha1_0 </ci>
              <ci> alpha1_infinity </ci>
            </apply>
            <apply>
              <plus/>
              <cn cellml:units="dimensionless"> 1.0 </cn>
              <apply>
                <exp/>
                <apply>
                  <divide/>
                  <apply>
                    <minus/>
                    <ci> Em </ci>
                    <ci> alpha1_E50 </ci>
                  </apply> 
                  <ci> alpha1_Eslope </ci>
                </apply>
              </apply>
            </apply>
          </apply>
        </apply>
      </apply>
      
      <apply id="rapid_delayed_rectifying_potassium_current_beta1_calculation">
        <eq/>
        <ci> beta1 </ci>
        <apply>
          <plus/>
          <ci> beta1_infinity </ci>
          <apply>
            <divide/>
            <apply>
              <minus/>
              <ci> beta1_0 </ci>
              <ci> beta1_infinity </ci>
            </apply>
            <apply>
              <plus/>
              <cn cellml:units="dimensionless"> 1.0 </cn>
              <apply>
                <exp/>
                <apply>
                  <divide/>
                  <apply>
                    <minus/>
                    <ci> Em </ci>
                    <ci> beta1_E50 </ci>
                  </apply> 
                  <ci> beta1_Eslope </ci>
                </apply>
              </apply>
            </apply>
          </apply>
        </apply>
      </apply>
      
      <apply id="rapid_delayed_rectifying_potassium_current_alpha2_calculation">
        <eq/>
        <ci> alpha2 </ci>
        <apply>
          <plus/>
          <ci> alpha2_infinity </ci>
          <apply>
            <divide/>
            <apply>
              <minus/>
              <ci> alpha2_0 </ci>
              <ci> alpha2_infinity </ci>
            </apply>
            <apply>
              <plus/>
              <cn cellml:units="dimensionless"> 1.0 </cn>
              <apply>
                <exp/>
                <apply>
                  <divide/>
                  <apply>
                    <minus/>
                    <ci> Em </ci>
                    <ci> alpha2_E50 </ci>
                  </apply> 
                  <ci> alpha2_Eslope </ci>
                </apply>
              </apply>
            </apply>
          </apply>
        </apply>
      </apply>
      
      <apply id="rapid_delayed_rectifying_potassium_current_alpha3_calculation">
        <eq/>
        <ci> alpha3 </ci>
        <apply>
          <plus/>
          <ci> alpha3_infinity </ci>
          <apply>
            <divide/>
            <apply>
              <minus/>
              <ci> alpha3_0 </ci>
              <ci> alpha3_infinity </ci>
            </apply>
            <apply>
              <plus/>
              <cn cellml:units="dimensionless"> 1.0 </cn>
              <apply>
                <exp/>
                <apply>
                  <divide/>
                  <apply>
                    <minus/>
                    <ci> Em </ci>
                    <ci> alpha3_E50 </ci>
                  </apply> 
                  <ci> alpha3_Eslope </ci>
                </apply>
              </apply>
            </apply>
          </apply>
        </apply>
      </apply>
      
      <apply id="rapid_delayed_rectifying_potassium_current_alpha4_calculation">
        <eq/>
        <ci> alpha4 </ci>
        <apply>
          <plus/>
          <ci> alpha4_infinity </ci>
          <apply>
            <divide/>
            <apply>
              <minus/>
              <ci> alpha4_0 </ci>
              <ci> alpha4_infinity </ci>
            </apply>
            <apply>
              <plus/>
              <cn cellml:units="dimensionless"> 1.0 </cn>
              <apply>
                <exp/>
                <apply>
                  <divide/>
                  <apply>
                    <minus/>
                    <ci> Em </ci>
                    <ci> alpha4_E50 </ci>
                  </apply> 
                  <ci> alpha4_Eslope </ci>
                </apply>
              </apply>
            </apply>
          </apply>
        </apply>
      </apply>
      
      <apply id="rapid_delayed_rectifying_potassium_current_beta4_calculation">
        <eq/>
        <ci> beta4 </ci>
        <apply>
          <plus/>
          <ci> beta4_infinity </ci>
          <apply>
            <divide/>
            <apply>
              <minus/>
              <ci> beta4_0 </ci>
              <ci> beta4_infinity </ci>
            </apply>
            <apply>
              <plus/>
              <cn cellml:units="dimensionless"> 1.0 </cn>
              <apply>
                <exp/>
                <apply>
                  <divide/>
                  <apply>
                    <minus/>
                    <ci> Em </ci>
                    <ci> beta4_E50 </ci>
                  </apply> 
                  <ci> beta4_Eslope </ci>
                </apply>
              </apply>
            </apply>
          </apply>
        </apply>
      </apply>
    </math>
  </component>
  
  <component name="slow_delayed_rectifying_potassium_current">
    <variable units="picoA" public_interface="out" name="i_Ks"/>
    <variable units="picoA" public_interface="out" name="i_Ks_Na"/>
    <variable units="picoA" public_interface="out" name="i_Ks_K"/>
    
    <variable units="nanoS" name="g_Ks" initial_value="1.328E1"/>
    <variable units="picoA_per_millimolar" name="PKNa_s" initial_value="3.053E-2"/>
    <variable units="dimensionless" name="A_Ks" initial_value="5.049E-3"/>
    <variable units="dimensionless" name="I1" initial_value="9.921E-1"/>
    <variable units="dimensionless" name="I2"/>
    <variable units="first_order_rate_constant" name="alpha1"/>
    <variable units="first_order_rate_constant" name="alpha2"/>
    <variable units="first_order_rate_constant" name="alpha3"/>
    <variable units="first_order_rate_constant" name="beta1"/>
    <variable units="first_order_rate_constant" name="beta3"/>
    <variable units="first_order_rate_constant" name="alpha1_0" initial_value="1.455"/>
    <variable units="first_order_rate_constant" name="alpha1_infinity" initial_value="1.590E1"/>
    <variable units="millivolt" name="alpha1_E50" initial_value="3.403E1"/>
    <variable units="millivolt" name="alpha1_Eslope" initial_value="9.464"/>
    <variable units="first_order_rate_constant" name="alpha2_0" initial_value="7.619E-1"/>
    <variable units="first_order_rate_constant" name="alpha2_infinity" initial_value="7.207E-2"/>
    <variable units="millivolt" name="alpha2_E50" initial_value="1.021E1"/>
    <variable units="millivolt" name="alpha2_Eslope" initial_value="2.584"/>
    <variable units="first_order_rate_constant" name="alpha3_0" initial_value="0.0"/>
    <variable units="first_order_rate_constant" name="alpha3_infinity" initial_value="1.690E1"/>
    <variable units="millivolt" name="alpha3_E50" initial_value="4.216E1"/>
    <variable units="millivolt" name="alpha3_Eslope" initial_value="8.481"/>
    <variable units="first_order_rate_constant" name="beta1_0" initial_value="3.628E-3"/>
    <variable units="first_order_rate_constant" name="beta1_infinity" initial_value="4.191"/>
    <variable units="millivolt" name="beta1_E50" initial_value="2.231E1"/>
    <variable units="millivolt" name="beta1_Eslope" initial_value="1.063E1"/>
    <variable units="first_order_rate_constant" name="beta3_0" initial_value="1.772"/>
    <variable units="first_order_rate_constant" name="beta3_infinity" initial_value="4.141E-1"/>
    <variable units="millivolt" name="beta3_E50" initial_value="9.822"/>
    <variable units="millivolt" name="beta3_Eslope" initial_value="1.280E1"/>
    
    <variable units="millivolt" public_interface="in" name="E_Na"/>
    <variable units="millivolt" public_interface="in" name="E_K"/>
    <variable units="second" public_interface="in" name="time"/>
    <variable units="millivolt" public_interface="in" name="Em"/>
    
    <math xmlns="http://www.w3.org/1998/Math/MathML">
      <apply id="i_Ks_calculation">
        <eq/>
        <ci> i_Ks </ci>
        <apply>
          <plus/>
          <ci> i_Ks_Na </ci>
          <ci> i_Ks_K </ci>
        </apply>
      </apply>
      
      <apply id="i_Ks_Na_calculation">
        <eq/>
        <ci> i_Ks_Na </ci>
        <apply>
          <times/>
          <ci> g_Ks </ci>
          <ci> A_Ks </ci>
          <ci> PKNa_s </ci>
          <apply>
            <minus/>
            <ci> Em </ci>
            <ci> E_Na </ci>
          </apply>
        </apply>
      </apply>
      
      <apply id="i_Ks_K_calculation">
        <eq/>
        <ci> i_Ks_K </ci>
        <apply>
          <times/>
          <ci> g_Ks </ci>
          <ci> A_Ks </ci>
          <apply>
            <minus/>
            <ci> Em </ci>
            <ci> E_K </ci>
          </apply>
        </apply>
      </apply>
      
      <apply id="dA_Ks_dt">
        <eq/>
        <apply>
          <diff/>
          <bvar>
            <ci> time </ci>
          </bvar>
          <ci> A_Ks </ci>
        </apply>
        <apply>
          <minus/>
          <apply>
            <times/>
            <ci> alpha1 </ci>
            <ci> I2 </ci>
          </apply>
          <apply>
            <times/>
            <apply>
              <plus/>
              <ci> beta1 </ci>
              <ci> alpha2 </ci>
            </apply>
            <ci> A_Ks </ci>
          </apply>
        </apply>
      </apply>
      
      <apply id="slow_delayed_rectifying_potassium_current_dI1_dt">
        <eq/>
        <apply>
          <diff/>
          <bvar>
            <ci> time </ci>
          </bvar>
          <ci> I1 </ci>
        </apply>
        <apply>
          <minus/>
          <apply>
            <plus/>
            <apply>
              <times/>
              <ci> alpha2 </ci>
              <ci> A_Ks </ci>
            </apply>
            <apply>
              <times/>
              <ci> beta3 </ci>
              <ci> I2 </ci>
            </apply>
          </apply>
          <apply>
            <times/>
            <ci> alpha3 </ci>
            <ci> I1 </ci>
          </apply>
        </apply>
      </apply>
      
      <apply id="slow_delayed_rectifying_potassium_current_dI2_dt">
        <eq/>
        <apply>
          <diff/>
          <bvar>
            <ci> time </ci>
          </bvar>
          <ci> I2 </ci>
        </apply>
        <apply>
          <minus/>
          <apply>
            <plus/>
            <apply>
              <times/>
              <ci> alpha3 </ci>
              <ci> I1 </ci>
            </apply>
            <apply>
              <times/>
              <ci> beta1 </ci>
              <ci> A_Ks </ci>
            </apply>
          </apply>
          <apply>
            <times/>
            <apply>
              <plus/>
              <ci> alpha1 </ci>
              <ci> beta3 </ci>
            </apply>
            <ci> I2 </ci>
          </apply>
        </apply>
      </apply>
      
      <apply id="slow_delayed_rectifying_potassium_current_alpha1_calculation">
        <eq/>
        <ci> alpha1 </ci>
        <apply>
          <plus/>
          <ci> alpha1_infinity </ci>
          <apply>
            <divide/>
            <apply>
              <minus/>
              <ci> alpha1_0 </ci>
              <ci> alpha1_infinity </ci>
            </apply>
            <apply>
              <plus/>
              <cn cellml:units="dimensionless"> 1.0 </cn>
              <apply>
                <exp/>
                <apply>
                  <divide/>
                  <apply>
                    <minus/>
                    <ci> Em </ci>
                    <ci> alpha1_E50 </ci>
                  </apply> 
                  <ci> alpha1_Eslope </ci>
                </apply>
              </apply>
            </apply>
          </apply>
        </apply>
      </apply>
      
      <apply id="slow_delayed_rectifying_potassium_current_beta1_calculation">
        <eq/>
        <ci> beta1 </ci>
        <apply>
          <plus/>
          <ci> beta1_infinity </ci>
          <apply>
            <divide/>
            <apply>
              <minus/>
              <ci> beta1_0 </ci>
              <ci> beta1_infinity </ci>
            </apply>
            <apply>
              <plus/>
              <cn cellml:units="dimensionless"> 1.0 </cn>
              <apply>
                <exp/>
                <apply>
                  <divide/>
                  <apply>
                    <minus/>
                    <ci> Em </ci>
                    <ci> beta1_E50 </ci>
                  </apply> 
                  <ci> beta1_Eslope </ci>
                </apply>
              </apply>
            </apply>
          </apply>
        </apply>
      </apply>
      
      <apply id="slow_delayed_rectifying_potassium_current_alpha2_calculation">
        <eq/>
        <ci> alpha2 </ci>
        <apply>
          <plus/>
          <ci> alpha2_infinity </ci>
          <apply>
            <divide/>
            <apply>
              <minus/>
              <ci> alpha2_0 </ci>
              <ci> alpha2_infinity </ci>
            </apply>
            <apply>
              <plus/>
              <cn cellml:units="dimensionless"> 1.0 </cn>
              <apply>
                <exp/>
                <apply>
                  <divide/>
                  <apply>
                    <minus/>
                    <ci> Em </ci>
                    <ci> alpha2_E50 </ci>
                  </apply> 
                  <ci> alpha2_Eslope </ci>
                </apply>
              </apply>
            </apply>
          </apply>
        </apply>
      </apply>
      
      <apply id="slow_delayed_rectifying_potassium_current_alpha3_calculation">
        <eq/>
        <ci> alpha3 </ci>
        <apply>
          <plus/>
          <ci> alpha3_infinity </ci>
          <apply>
            <divide/>
            <apply>
              <minus/>
              <ci> alpha3_0 </ci>
              <ci> alpha3_infinity </ci>
            </apply>
            <apply>
              <plus/>
              <cn cellml:units="dimensionless"> 1.0 </cn>
              <apply>
                <exp/>
                <apply>
                  <divide/>
                  <apply>
                    <minus/>
                    <ci> Em </ci>
                    <ci> alpha3_E50 </ci>
                  </apply> 
                  <ci> alpha3_Eslope </ci>
                </apply>
              </apply>
            </apply>
          </apply>
        </apply>
      </apply>
      
      <apply id="slow_delayed_rectifying_potassium_current_beta3_calculation">
        <eq/>
        <ci> beta3 </ci>
        <apply>
          <plus/>
          <ci> beta3_infinity </ci>
          <apply>
            <divide/>
            <apply>
              <minus/>
              <ci> beta3_0 </ci>
              <ci> beta3_infinity </ci>
            </apply>
            <apply>
              <plus/>
              <cn cellml:units="dimensionless"> 1.0 </cn>
              <apply>
                <exp/>
                <apply>
                  <divide/>
                  <apply>
                    <minus/>
                    <ci> Em </ci>
                    <ci> beta3_E50 </ci>
                  </apply> 
                  <ci> beta3_Eslope </ci>
                </apply>
              </apply>
            </apply>
          </apply>
        </apply>
      </apply>
    </math>
  </component>
  
  <component name="TTX_sensitive_sodium_current">
    <variable units="picoA" public_interface="out" name="i_Na"/>
    <variable units="nanoS" public_interface="out" name="g_Na" initial_value="2.889"/>
    
    <variable units="dimensionless" name="A_Na" initial_value="5.586E-4"/>
    <variable units="dimensionless" name="I1" initial_value="3.750E-1"/>
    <variable units="dimensionless" name="I2" initial_value="1.039E-1"/>
    <variable units="dimensionless" name="I3"/>
    <variable units="first_order_rate_constant" name="alpha1"/>
    <variable units="first_order_rate_constant" name="alpha2"/>
    <variable units="first_order_rate_constant" name="alpha3"/>
    <variable units="first_order_rate_constant" name="alpha4"/>
    <variable units="first_order_rate_constant" name="beta1"/>
    <variable units="first_order_rate_constant" name="beta4"/>
    <variable units="first_order_rate_constant" name="alpha1_0" initial_value="1.022E-31"/>
    <variable units="first_order_rate_constant" name="alpha1_infinity" initial_value="4.355E5"/>
    <variable units="millivolt" name="alpha1_E50" initial_value="-3.808E1"/>
    <variable units="millivolt" name="alpha1_Eslope" initial_value="4.402"/>
    <variable units="first_order_rate_constant" name="alpha2_0" initial_value="2.950E1"/>
    <variable units="first_order_rate_constant" name="alpha2_infinity" initial_value="1.710E2"/>
    <variable units="millivolt" name="alpha2_E50" initial_value="-1.841E1"/>
    <variable units="millivolt" name="alpha2_Eslope" initial_value="1.661E1"/>
    <variable units="first_order_rate_constant" name="alpha3_0" initial_value="0.0"/>
    <variable units="first_order_rate_constant" name="alpha3_infinity" initial_value="2.031"/>
    <variable units="millivolt" name="alpha3_E50" initial_value="-3.004E1"/>
    <variable units="millivolt" name="alpha3_Eslope" initial_value="1.275E-1"/>
    <variable units="first_order_rate_constant" name="alpha4_0" initial_value="6.000E1"/>
    <variable units="first_order_rate_constant" name="alpha4_infinity" initial_value="0.0"/>
    <variable units="millivolt" name="alpha4_E50" initial_value="-5.556E1"/>
    <variable units="millivolt" name="alpha4_Eslope" initial_value="4.849"/>
    <variable units="first_order_rate_constant" name="beta1_0" initial_value="1.133E6"/>
    <variable units="first_order_rate_constant" name="beta1_infinity" initial_value="4.104E5"/>
    <variable units="millivolt" name="beta1_E50" initial_value="-2.239"/>
    <variable units="millivolt" name="beta1_Eslope" initial_value="1.651"/>
    <variable units="first_order_rate_constant" name="beta4_0" initial_value="1.831E-4"/>
    <variable units="first_order_rate_constant" name="beta4_infinity" initial_value="1.904E3"/>
    <variable units="millivolt" name="beta4_E50" initial_value="1.821E1"/>
    <variable units="millivolt" name="beta4_Eslope" initial_value="1.466E1"/>
    
    <variable units="millivolt" public_interface="in" name="E_Na"/>
    <variable units="second" public_interface="in" name="time"/>
    <variable units="millivolt" public_interface="in" name="Em"/>
    
    <math xmlns="http://www.w3.org/1998/Math/MathML">
      <apply id="i_Na_calculation">
        <eq/>
        <ci> i_Na </ci>
        <apply>
          <times/>
          <ci> g_Na </ci>
          <ci> A_Na </ci>
          <apply>
            <minus/>
            <ci> Em </ci>
            <ci> E_Na </ci>
          </apply>
        </apply>
      </apply>
      
      <apply id="dA_Na_dt">
        <eq/>
        <apply>
          <diff/>
          <bvar>
            <ci> time </ci>
          </bvar>
          <ci> A_Na </ci>
        </apply>
        <apply>
          <minus/>
          <apply>
            <times/>
            <ci> alpha1 </ci>
            <ci> I3 </ci>
          </apply>
          <apply>
            <times/>
            <apply>
              <plus/>
              <ci> beta1 </ci>
              <ci> alpha2 </ci>
            </apply>
            <ci> A_Na </ci>
          </apply>
        </apply>
      </apply>
      
      <apply id="TTX_sensitive_sodium_current_dI1_dt">
        <eq/>
        <apply>
          <diff/>
          <bvar>
            <ci> time </ci>
          </bvar>
          <ci> I1 </ci>
        </apply>
        <apply>
          <minus/>
          <apply>
            <times/>
            <ci> alpha2 </ci>
            <ci> A_Na </ci>
          </apply>
          <apply>
            <times/>
            <ci> alpha3 </ci>
            <ci> I1 </ci>
          </apply>
        </apply>
      </apply>
      
      <apply id="TTX_sensitive_sodium_current_dI2_dt">
        <eq/>
        <apply>
          <diff/>
          <bvar>
            <ci> time </ci>
          </bvar>
          <ci> I2 </ci>
        </apply>
        <apply>
          <minus/>
          <apply>
            <plus/>
            <apply>
              <times/>
              <ci> alpha3 </ci>
              <ci> I1 </ci>
            </apply>
            <apply>
              <times/>
              <ci> beta4 </ci>
              <ci> I3 </ci>
            </apply>
          </apply>
          <apply>
            <times/>
            <ci> alpha4 </ci>
            <ci> I2 </ci>
          </apply>
        </apply>
      </apply>
      
      <apply id="TTX_sensitive_sodium_current_dI3_dt">
        <eq/>
        <apply>
          <diff/>
          <bvar>
            <ci> time </ci>
          </bvar>
          <ci> I3 </ci>
        </apply>
        <apply>
          <minus/>
          <apply>
            <plus/>
            <apply>
              <times/>
              <ci> beta1 </ci>
              <ci> A_Na </ci>
            </apply>
            <apply>
              <times/>
              <ci> alpha4 </ci>
              <ci> I2 </ci>
            </apply>
          </apply>
          <apply>
            <times/>
            <apply>
              <plus/>
              <ci> alpha1 </ci>
              <ci> beta4 </ci>
            </apply>
            <ci> I3 </ci>
          </apply>
        </apply>
      </apply>
      
      <apply id="TTX_sensitive_sodium_current_alpha1_calculation">
        <eq/>
        <ci> alpha1 </ci>
        <apply>
          <plus/>
          <ci> alpha1_infinity </ci>
          <apply>
            <divide/>
            <apply>
              <minus/>
              <ci> alpha1_0 </ci>
              <ci> alpha1_infinity </ci>
            </apply>
            <apply>
              <plus/>
              <cn cellml:units="dimensionless"> 1.0 </cn>
              <apply>
                <exp/>
                <apply>
                  <divide/>
                  <apply>
                    <minus/>
                    <ci> Em </ci>
                    <ci> alpha1_E50 </ci>
                  </apply> 
                  <ci> alpha1_Eslope </ci>
                </apply>
              </apply>
            </apply>
          </apply>
        </apply>
      </apply>
      
      <apply id="TTX_sensitive_sodium_current_beta1_calculation">
        <eq/>
        <ci> beta1 </ci>
        <apply>
          <plus/>
          <ci> beta1_infinity </ci>
          <apply>
            <divide/>
            <apply>
              <minus/>
              <ci> beta1_0 </ci>
              <ci> beta1_infinity </ci>
            </apply>
            <apply>
              <plus/>
              <cn cellml:units="dimensionless"> 1.0 </cn>
              <apply>
                <exp/>
                <apply>
                  <divide/>
                  <apply>
                    <minus/>
                    <ci> Em </ci>
                    <ci> beta1_E50 </ci>
                  </apply> 
                  <ci> beta1_Eslope </ci>
                </apply>
              </apply>
            </apply>
          </apply>
        </apply>
      </apply>
      
      <apply id="TTX_sensitive_sodium_current_alpha2_calculation">
        <eq/>
        <ci> alpha2 </ci>
        <apply>
          <plus/>
          <ci> alpha2_infinity </ci>
          <apply>
            <divide/>
            <apply>
              <minus/>
              <ci> alpha2_0 </ci>
              <ci> alpha2_infinity </ci>
            </apply>
            <apply>
              <plus/>
              <cn cellml:units="dimensionless"> 1.0 </cn>
              <apply>
                <exp/>
                <apply>
                  <divide/>
                  <apply>
                    <minus/>
                    <ci> Em </ci>
                    <ci> alpha2_E50 </ci>
                  </apply> 
                  <ci> alpha2_Eslope </ci>
                </apply>
              </apply>
            </apply>
          </apply>
        </apply>
      </apply>
      
      <apply id="TTX_sensitive_sodium_current_alpha3_calculation">
        <eq/>
        <ci> alpha3 </ci>
        <apply>
          <plus/>
          <ci> alpha3_infinity </ci>
          <apply>
            <divide/>
            <apply>
              <minus/>
              <ci> alpha3_0 </ci>
              <ci> alpha3_infinity </ci>
            </apply>
            <apply>
              <plus/>
              <cn cellml:units="dimensionless"> 1.0 </cn>
              <apply>
                <exp/>
                <apply>
                  <divide/>
                  <apply>
                    <minus/>
                    <ci> Em </ci>
                    <ci> alpha3_E50 </ci>
                  </apply> 
                  <ci> alpha3_Eslope </ci>
                </apply>
              </apply>
            </apply>
          </apply>
        </apply>
      </apply>
      
      <apply id="TTX_sensitive_sodium_current_alpha4_calculation">
        <eq/>
        <ci> alpha4 </ci>
        <apply>
          <plus/>
          <ci> alpha4_infinity </ci>
          <apply>
            <divide/>
            <apply>
              <minus/>
              <ci> alpha4_0 </ci>
              <ci> alpha4_infinity </ci>
            </apply>
            <apply>
              <plus/>
              <cn cellml:units="dimensionless"> 1.0 </cn>
              <apply>
                <exp/>
                <apply>
                  <divide/>
                  <apply>
                    <minus/>
                    <ci> Em </ci>
                    <ci> alpha4_E50 </ci>
                  </apply> 
                  <ci> alpha4_Eslope </ci>
                </apply>
              </apply>
            </apply>
          </apply>
        </apply>
      </apply>
      
      <apply id="TTX_sensitive_sodium_current_beta4_calculation">
        <eq/>
        <ci> beta4 </ci>
        <apply>
          <plus/>
          <ci> beta4_infinity </ci>
          <apply>
            <divide/>
            <apply>
              <minus/>
              <ci> beta4_0 </ci>
              <ci> beta4_infinity </ci>
            </apply>
            <apply>
              <plus/>
              <cn cellml:units="dimensionless"> 1.0 </cn>
              <apply>
                <exp/>
                <apply>
                  <divide/>
                  <apply>
                    <minus/>
                    <ci> Em </ci>
                    <ci> beta4_E50 </ci>
                  </apply> 
                  <ci> beta4_Eslope </ci>
                </apply>
              </apply>
            </apply>
          </apply>
        </apply>
      </apply>
    </math>
  </component>
  
  <component name="sodium_calcium_exchange_current">
    <variable units="picoA" public_interface="out" name="i_NaCa"/>
    
    <variable units="picoA" name="kNaCa" initial_value="2.249E3"/>
    <variable units="dimensionless" name="x1"/>
    <variable units="dimensionless" name="x2"/>
    <variable units="dimensionless" name="x3"/>
    <variable units="dimensionless" name="x4"/>
    <variable units="dimensionless" name="k41"/>
    <variable units="dimensionless" name="k34"/>
    <variable units="dimensionless" name="k23"/>
    <variable units="dimensionless" name="k21"/>
    <variable units="dimensionless" name="k32"/>
    <variable units="dimensionless" name="k43"/>
    <variable units="dimensionless" name="k12"/>
    <variable units="dimensionless" name="k14"/>
    <variable units="dimensionless" name="Qci" initial_value="1.421E-1"/>
    <variable units="dimensionless" name="Qn" initial_value="2.650E-1"/>
    <variable units="dimensionless" name="Qco" initial_value="0.0"/>
    <variable units="millimolar" name="K3ni" initial_value="2.490E1"/>
    <variable units="millimolar" name="Kci" initial_value="6.510E-3"/>
    <variable units="millimolar" name="K1ni" initial_value="3.938E2"/>
    <variable units="millimolar" name="K2ni" initial_value="2.286"/>
    <variable units="millimolar" name="Kcni" initial_value="2.568E1"/>
    <variable units="millimolar" name="K3no" initial_value="6.325"/>
    <variable units="millimolar" name="K1no" initial_value="2.200E3"/>
    <variable units="millimolar" name="K2no" initial_value="7.639E2"/>
    <variable units="millimolar" name="Kco" initial_value="3.299"/>
    <variable units="dimensionless" name="D1"/>
    <variable units="dimensionless" name="D2"/>
    
    <variable units="millimolar" public_interface="in" name="Cai"/>
    <variable units="millimolar" public_interface="in" name="Cao"/>
    <variable units="millimolar" public_interface="in" name="Nao"/>
    <variable units="millimolar" public_interface="in" name="Nai"/>
    <variable units="joule_per_mole_kelvin" public_interface="in" name="R"/>
    <variable units="kelvin" public_interface="in" name="T"/>
    <variable units="coulomb_per_mole" public_interface="in" name="F"/>
    <variable units="millivolt" public_interface="in" name="Em"/>
    
    <math xmlns="http://www.w3.org/1998/Math/MathML">
      <apply id="i_NaCa_calculation">
        <eq/>
        <ci> i_NaCa </ci>
        <apply>
          <times/>
          <ci> kNaCa </ci>
          <apply>
            <divide/>
            <apply>
              <minus/>
              <apply>
                <times/>
                <ci> x2 </ci>
                <ci> k21 </ci>
              </apply>
              <apply>
                <times/>
                <ci> x1 </ci>
                <ci> k12 </ci>
              </apply>
            </apply>
            <apply>
              <plus/>
              <ci> x1 </ci>
              <ci> x2 </ci>
              <ci> x3 </ci>
              <ci> x4 </ci>
            </apply>
          </apply>
        </apply>
      </apply>
     
      <apply id="x1_calculation">
        <eq/>
        <ci> x1 </ci>
        <apply>
          <plus/>
          <apply>
            <times/>
            <ci> k41 </ci>
            <ci> k34 </ci>
            <apply>
              <plus/>
              <ci> k23 </ci>
              <ci> k21 </ci>
            </apply>
          </apply>
          <apply>
            <times/>
            <ci> k21 </ci>
            <ci> k32 </ci>
            <apply>
              <plus/>
              <ci> k43 </ci>
              <ci> k41 </ci>
            </apply>
          </apply>
        </apply>
      </apply>
      
      <apply id="x2_calculation">
        <eq/>
        <ci> x2 </ci>
        <apply>
          <plus/>
          <apply>
            <times/>
            <ci> k32 </ci>
            <ci> k43 </ci>
            <apply>
              <plus/>
              <ci> k14 </ci>
              <ci> k12 </ci>
            </apply>
          </apply>
          <apply>
            <times/>
            <ci> k41 </ci>
            <ci> k12 </ci>
            <apply>
              <plus/>
              <ci> k34 </ci>
              <ci> k32 </ci>
            </apply>
          </apply>
        </apply>
      </apply>
      
      <apply id="x3_calculation">
        <eq/>
        <ci> x3 </ci>
        <apply>
          <plus/>
          <apply>
            <times/>
            <ci> k14 </ci>
            <ci> k43 </ci>
            <apply>
              <plus/>
              <ci> k23 </ci>
              <ci> k21 </ci>
            </apply>
          </apply>
          <apply>
            <times/>
            <ci> k12 </ci>
            <ci> k23 </ci>
            <apply>
              <plus/>
              <ci> k43 </ci>
              <ci> k41 </ci>
            </apply>
          </apply>
        </apply>
      </apply>
      
      <apply id="x4_calculation">
        <eq/>
        <ci> x4 </ci>
        <apply>
          <plus/>
          <apply>
            <times/>
            <ci> k23 </ci>
            <ci> k34 </ci>
            <apply>
              <plus/>
              <ci> k14 </ci>
              <ci> k12 </ci>
            </apply>
          </apply>
          <apply>
            <times/>
            <ci> k14 </ci>
            <ci> k21 </ci>
            <apply>
              <plus/>
              <ci> k34 </ci>
              <ci> k32 </ci>
            </apply>
          </apply>
        </apply>
      </apply>
      
      <apply id="k43_calculation">
        <eq/>
        <ci> k43 </ci>
        <apply>
          <divide/>
          <ci> Nai </ci>
          <apply>
            <plus/>
            <ci> K3ni </ci>
            <ci> Nai </ci>
          </apply>
        </apply>
      </apply>
      
      <apply id="k12_calculation">
        <eq/>
        <ci> k12 </ci>
        <apply>
          <divide/>
          <apply>
            <times/>
            <ci> Cai </ci>
            <apply>
              <exp/>
              <apply>
                <minus/>
                <apply>
                  <divide/>
                  <apply>
                    <times/>
                    <ci> Em </ci>
                    <ci> Qci </ci>
                    <ci> F </ci>
                  </apply>
                  <apply>
                    <times/>
                    <ci> R </ci>
                    <ci> T </ci>
                  </apply>
                </apply>
              </apply>
            </apply>
          </apply> 
          <apply>
            <times/>
            <ci> Kci </ci>
            <ci> D1 </ci>
          </apply>
        </apply>
      </apply>
      
      <apply id="k14_calculation">
        <eq/>
        <ci> k14 </ci>
        <apply>
          <divide/>
          <apply>
            <times/>
            <apply>
              <power/>
              <ci> Nai </ci>
              <cn cellml:units="dimensionless"> 2.0 </cn>
            </apply>
            <apply>
              <plus/>
              <cn cellml:units="dimensionless"> 1.0 </cn>
              <apply>
                <divide/>
                <ci> Nai </ci>
                <ci> K3ni </ci>
              </apply>
            </apply>
            <apply>
              <exp/>
              <apply>
                <divide/>
                <apply>
                  <times/>
                  <ci> Qn </ci>
                  <ci> Em </ci>
                  <ci> F </ci>
                </apply>
                <apply>
                  <times/>
                  <cn cellml:units="dimensionless"> 2.0 </cn>
                  <ci> R </ci>
                  <ci> T </ci>
                </apply>
              </apply>
            </apply>
          </apply>
          <apply>
            <times/>
            <ci> K1ni </ci>
            <ci> K2ni </ci>
            <ci> D1 </ci>
          </apply>
        </apply>
      </apply>
      
      <apply id="k41_calculation">
        <eq/>
        <ci> k41 </ci>
        <apply>
          <exp/>
          <apply>
            <minus/>
            <apply>
              <divide/>
              <apply>
                <times/>
                <ci> Em </ci>
                <ci> Qn </ci>
                <ci> F </ci>
              </apply>
              <apply>
                <times/>
                <cn cellml:units="dimensionless"> 2.0 </cn>
                <ci> R </ci>
                <ci> T </ci>
              </apply>
            </apply>
          </apply>
        </apply>
      </apply>
      
      <apply id="D1_calculation">
        <eq/>
        <ci> D1 </ci>
        <apply>
          <plus/>
          <cn cellml:units="dimensionless"> 1.0 </cn>
          <apply>
            <times/>
            <apply>
              <divide/>
              <ci> Cai </ci>
              <ci> Kci </ci>
            </apply>
            <apply>
              <plus/>
              <cn cellml:units="dimensionless"> 1.0 </cn>
              <apply>
                <exp/>
                <apply>
                  <minus/>
                  <apply>
                    <divide/>
                    <apply>
                      <times/>
                      <ci> Em </ci>
                      <ci> Qci </ci>
                      <ci> F </ci>
                    </apply>
                    <apply>
                      <times/>
                      <ci> R </ci>
                      <ci> T </ci>
                    </apply>
                  </apply>
                </apply>
              </apply>
            </apply>
            <apply>
              <divide/>
              <apply>
                <times/>
                <ci> Cai </ci>
                <ci> Nai </ci>
              </apply>
              <apply>
                <times/>
                <ci> Kci </ci>
                <ci> Kcni </ci>
              </apply>
            </apply>
          </apply>
          <apply>
            <times/>
            <apply>
              <divide/>
              <ci> Nai </ci>
              <ci> K1ni </ci>
            </apply>
            <apply>
              <plus/>
              <cn cellml:units="dimensionless"> 1.0 </cn>
              <apply>
                <times/>
                <apply>
                  <divide/>
                  <ci> Nai </ci>
                  <ci> K2ni </ci>
                </apply>
                <apply>
                  <plus/>
                  <cn cellml:units="dimensionless"> 1.0 </cn>
                  <apply>
                    <divide/>
                    <ci> Nai </ci>
                    <ci> K3ni </ci>
                  </apply>
                </apply>
              </apply>
            </apply>
          </apply>
        </apply>
      </apply>
      
      <apply id="k34_calculation">
        <eq/>
        <ci> k34 </ci>
        <apply>
          <divide/>
          <ci> Nao </ci>
          <apply>
            <plus/>
            <ci> K3no </ci>
            <ci> Nao </ci>
          </apply>
        </apply>
      </apply> 
      
      <apply id="k21_calculation">
        <eq/>
        <ci> k21 </ci>
        <apply>
          <divide/>
          <apply>
            <times/>
            <apply>
              <divide/>
              <ci> Cao </ci>
              <ci> Kco </ci>
            </apply>
            <apply>
              <exp/>
              <apply>
                <divide/>
                <apply>
                  <times/>
                  <ci> Qco </ci>
                  <ci> Em </ci>
                  <ci> F </ci>
                </apply>
                <apply>
                  <times/>
                  <ci> R </ci>
                  <ci> T </ci>
                </apply>
              </apply>
            </apply>
          </apply>
          <ci> D2 </ci>
        </apply>
      </apply>   
      
      <apply id="k23_calculation">
        <eq/>
        <ci> k23 </ci>
        <apply>
          <divide/>
          <apply>
            <times/>
            <apply>
              <power/>
              <ci> Nao </ci>
              <cn cellml:units="dimensionless"> 2.0 </cn>
            </apply>
            <apply>
              <plus/>
              <cn cellml:units="dimensionless"> 1.0 </cn>
              <apply>
                <divide/>
                <ci> Nao </ci>
                <ci> K3no </ci>
              </apply>
            </apply>
            <apply>
              <exp/>
              <apply>
                <minus/>
                <apply>
                  <divide/>
                  <apply>
                    <times/>
                    <ci> Qn </ci>
                    <ci> Em </ci>
                    <ci> F </ci>
                  </apply>
                  <apply>
                    <times/>
                    <cn cellml:units="dimensionless"> 2.0 </cn>
                    <ci> R </ci>
                    <ci> T </ci>
                  </apply>
                </apply>
              </apply>
            </apply>
          </apply>
          <apply>
            <times/>
            <ci> K1no </ci>
            <ci> K2no </ci>
            <ci> D2 </ci>
          </apply>
        </apply>
      </apply>
      
      <apply id="k32_calculation">
        <eq/>
        <ci> k32 </ci>
        <apply>
          <exp/>
          <apply>
            <divide/>
            <apply>
              <times/>
              <ci> Qn </ci>
              <ci> Em </ci>
              <ci> F </ci>
            </apply>
            <apply>
              <times/>
              <cn cellml:units="dimensionless"> 2.0 </cn>
              <ci> R </ci>
              <ci> T </ci>
            </apply>
          </apply>
        </apply>
      </apply>
      
      <apply id="D2_calculation">
        <eq/>
        <ci> D2 </ci>
        <apply>
          <plus/>
          <cn cellml:units="dimensionless"> 1.0 </cn>
          <apply>
            <times/>
            <apply>
              <divide/>
              <ci> Cao </ci>
              <ci> Kco </ci>
            </apply>
            <apply>
              <plus/>
              <cn cellml:units="dimensionless"> 1.0 </cn>
              <apply>
                <exp/>
                <apply>
                  <divide/>
                  <apply>
                    <times/>
                    <ci> Qco </ci>
                    <ci> Em </ci>
                    <ci> F </ci>
                  </apply>
                  <apply>
                    <times/>
                    <ci> R </ci>
                    <ci> T </ci>
                  </apply>
                </apply>
              </apply>
            </apply>
          </apply>
          <apply>
            <times/>
            <apply>
              <divide/>
              <ci> Nao </ci>
              <ci> K1no </ci>
            </apply>
            <apply>
              <plus/>
              <cn cellml:units="dimensionless"> 1.0 </cn>
              <apply>
                <divide/>
                <ci> Nao </ci>
                <ci> K2no </ci>
              </apply>
            </apply>
            <apply>
              <plus/>
              <cn cellml:units="dimensionless"> 1.0 </cn>
              <apply>
                <divide/>
                <ci> Nao </ci>
                <ci> K3no </ci>
              </apply>
            </apply>
          </apply> 
        </apply>
      </apply>     
    </math>
  </component>
  
  <component name="hyperpolarisation_activated_current">
    <variable units="picoA" public_interface="out" name="i_f"/>
    <variable units="picoA" public_interface="out" name="i_fNa"/>
    <variable units="picoA" public_interface="out" name="i_fK"/>
    
    <variable units="dimensionless" name="P_f_K" initial_value="1.162"/>
    <variable units="nanoS" name="g_f_Na" initial_value="5.031E2"/>
    <variable units="nanoS" name="g_f_K"/>
    <variable units="dimensionless" name="A_f" initial_value="3.716E-4"/>
    <variable units="millimolar" name="Km_f" initial_value="1.030E1"/>
    <variable units="dimensionless" name="I1" initial_value="9.972E-1"/>
    <variable units="dimensionless" name="I2"/>
    <variable units="first_order_rate_constant" name="alpha1"/>
    <variable units="first_order_rate_constant" name="alpha2"/>
    <variable units="first_order_rate_constant" name="alpha3"/>
    <variable units="first_order_rate_constant" name="beta1"/>
    <variable units="first_order_rate_constant" name="beta3"/>
    <variable units="first_order_rate_constant" name="alpha1_0" initial_value="1.244"/>
    <variable units="first_order_rate_constant" name="alpha1_infinity" initial_value="2.157"/>
    <variable units="millivolt" name="alpha1_E50" initial_value="-4.973E1"/>
    <variable units="millivolt" name="alpha1_Eslope" initial_value="9.458"/>
    <variable units="first_order_rate_constant" name="alpha2_0" initial_value="0.0"/>
    <variable units="first_order_rate_constant" name="alpha2_infinity" initial_value="6.951"/>
    <variable units="millivolt" name="alpha2_E50" initial_value="-6.658E1"/>
    <variable units="millivolt" name="alpha2_Eslope" initial_value="1.013E1"/>
    <variable units="first_order_rate_constant" name="alpha3_0" initial_value="5.826"/>
    <variable units="first_order_rate_constant" name="alpha3_infinity" initial_value="0.0"/>
    <variable units="millivolt" name="alpha3_E50" initial_value="-1.235E2"/>
    <variable units="millivolt" name="alpha3_Eslope" initial_value="1.036E1"/>
    <variable units="first_order_rate_constant" name="beta1_0" initial_value="9.584E-3"/>
    <variable units="first_order_rate_constant" name="beta1_infinity" initial_value="2.619E1"/>
    <variable units="millivolt" name="beta1_E50" initial_value="-2.529E1"/>
    <variable units="millivolt" name="beta1_Eslope" initial_value="6.206"/>
    <variable units="first_order_rate_constant" name="beta3_0" initial_value="0.0"/>
    <variable units="first_order_rate_constant" name="beta3_infinity" initial_value="1.507E1"/>
    <variable units="millivolt" name="beta3_E50" initial_value="-7.443"/>
    <variable units="millivolt" name="beta3_Eslope" initial_value="1.323E1"/>
    
    <variable units="millimolar" public_interface="in" name="Ko"/>
    <variable units="millivolt" public_interface="in" name="E_Na"/>
    <variable units="millivolt" public_interface="in" name="E_K"/>
    <variable units="second" public_interface="in" name="time"/>
    <variable units="millivolt" public_interface="in" name="Em"/>
    
    <math xmlns="http://www.w3.org/1998/Math/MathML">
      <apply id="i_f_calculation">
        <eq/>
        <ci> i_f </ci>
        <apply>
          <plus/>
          <ci> i_fNa </ci>
          <ci> i_fK </ci>
        </apply>
      </apply>
      
      <apply id="i_fNa_calculation">
        <eq/>
        <ci> i_fNa </ci>
        <apply>
          <times/>
          <ci> A_f </ci>
          <apply>
            <divide/>
            <apply>
              <power/>
              <ci> Ko </ci>
              <cn cellml:units="dimensionless"> 1.83 </cn>
            </apply>
            <apply>
              <plus/>
              <apply>
                <power/>
                <ci> Ko </ci>
                <cn cellml:units="dimensionless"> 1.83 </cn>
              </apply>
              <apply>
                <power/>
                <ci> Km_f </ci>
                <cn cellml:units="dimensionless"> 1.83 </cn>
              </apply>
            </apply>
          </apply>
          <ci> g_f_Na </ci>
          <apply>
            <minus/>
            <ci> Em </ci>
            <ci> E_Na </ci>
          </apply>
        </apply>
      </apply>
      
      <apply id="i_fK_calculation">
        <eq/>
        <ci> i_fK </ci>
        <apply>
          <times/>
          <ci> A_f </ci>
          <apply>
            <divide/>
            <apply>
              <power/>
              <ci> Ko </ci>
              <cn cellml:units="dimensionless"> 1.83 </cn>
            </apply>
            <apply>
              <plus/>
              <apply>
                <power/>
                <ci> Ko </ci>
                <cn cellml:units="dimensionless"> 1.83 </cn>
              </apply>
              <apply>
                <power/>
                <ci> Km_f </ci>
                <cn cellml:units="dimensionless"> 1.83 </cn>
              </apply>
            </apply>
          </apply>
          <ci> P_f_K </ci>
          <ci> g_f_K </ci>
          <apply>
            <minus/>
            <ci> Em </ci>
            <ci> E_K </ci>
          </apply>
        </apply>
      </apply>
     
      <apply id="dA_f_dt">
        <eq/>
        <apply>
          <diff/>
          <bvar>
            <ci> time </ci>
          </bvar>
          <ci> A_f </ci>
        </apply>
        <apply>
          <minus/>
          <apply>
            <times/>
            <ci> alpha1 </ci>
            <ci> I2 </ci>
          </apply>
          <apply>
            <times/>
            <apply>
              <plus/>
              <ci> beta1 </ci>
              <ci> alpha2 </ci>
            </apply>
            <ci> A_f </ci>
          </apply>
        </apply>
      </apply>
      
      <apply id="hyperpolarisation_activated_current_dI1_dt">
        <eq/>
        <apply>
          <diff/>
          <bvar>
            <ci> time </ci>
          </bvar>
          <ci> I1 </ci>
        </apply>
        <apply>
          <minus/>
          <apply>
            <plus/>
            <apply>
              <times/>
              <ci> alpha2 </ci>
              <ci> A_f </ci>
            </apply>
            <apply>
              <times/>
              <ci> beta3 </ci>
              <ci> I2 </ci>
            </apply>
          </apply>
          <apply>
            <times/>
            <ci> alpha3 </ci>
            <ci> I1 </ci>
          </apply>
        </apply>
      </apply>
      
      <apply id="hyperpolarisation_activated_current_dI2_dt">
        <eq/>
        <apply>
          <diff/>
          <bvar>
            <ci> time </ci>
          </bvar>
          <ci> I2 </ci>
        </apply>
        <apply>
          <minus/>
          <apply>
            <plus/>
            <apply>
              <times/>
              <ci> alpha3 </ci>
              <ci> I1 </ci>
            </apply>
            <apply>
              <times/>
              <ci> beta1 </ci>
              <ci> A_f </ci>
            </apply>
          </apply>
          <apply>
            <times/>
            <apply>
              <plus/>
              <ci> beta3 </ci>
              <ci> alpha1 </ci>
            </apply>
            <ci> I2 </ci>
          </apply>
        </apply>
      </apply>
      
      <apply id="hyperpolarisation_activated_current_alpha1_calculation">
        <eq/>
        <ci> alpha1 </ci>
        <apply>
          <plus/>
          <ci> alpha1_infinity </ci>
          <apply>
            <divide/>
            <apply>
              <minus/>
              <ci> alpha1_0 </ci>
              <ci> alpha1_infinity </ci>
            </apply>
            <apply>
              <plus/>
              <cn cellml:units="dimensionless"> 1.0 </cn>
              <apply>
                <exp/>
                <apply>
                  <divide/>
                  <apply>
                    <minus/>
                    <ci> Em </ci>
                    <ci> alpha1_E50 </ci>
                  </apply> 
                  <ci> alpha1_Eslope </ci>
                </apply>
              </apply>
            </apply>
          </apply>
        </apply>
      </apply>
      
      <apply id="hyperpolarisation_activated_current_beta1_calculation">
        <eq/>
        <ci> beta1 </ci>
        <apply>
          <plus/>
          <ci> beta1_infinity </ci>
          <apply>
            <divide/>
            <apply>
              <minus/>
              <ci> beta1_0 </ci>
              <ci> beta1_infinity </ci>
            </apply>
            <apply>
              <plus/>
              <cn cellml:units="dimensionless"> 1.0 </cn>
              <apply>
                <exp/>
                <apply>
                  <divide/>
                  <apply>
                    <minus/>
                    <ci> Em </ci>
                    <ci> beta1_E50 </ci>
                  </apply> 
                  <ci> beta1_Eslope </ci>
                </apply>
              </apply>
            </apply>
          </apply>
        </apply>
      </apply>
      
      <apply id="hyperpolarisation_activated_current_alpha2_calculation">
        <eq/>
        <ci> alpha2 </ci>
        <apply>
          <plus/>
          <ci> alpha2_infinity </ci>
          <apply>
            <divide/>
            <apply>
              <minus/>
              <ci> alpha2_0 </ci>
              <ci> alpha2_infinity </ci>
            </apply>
            <apply>
              <plus/>
              <cn cellml:units="dimensionless"> 1.0 </cn>
              <apply>
                <exp/>
                <apply>
                  <divide/>
                  <apply>
                    <minus/>
                    <ci> Em </ci>
                    <ci> alpha2_E50 </ci>
                  </apply> 
                  <ci> alpha2_Eslope </ci>
                </apply>
              </apply>
            </apply>
          </apply>
        </apply>
      </apply>
      
      <apply id="hyperpolarisation_activated_current_alpha3_calculation">
        <eq/>
        <ci> alpha3 </ci>
        <apply>
          <plus/>
          <ci> alpha3_infinity </ci>
          <apply>
            <divide/>
            <apply>
              <minus/>
              <ci> alpha3_0 </ci>
              <ci> alpha3_infinity </ci>
            </apply>
            <apply>
              <plus/>
              <cn cellml:units="dimensionless"> 1.0 </cn>
              <apply>
                <exp/>
                <apply>
                  <divide/>
                  <apply>
                    <minus/>
                    <ci> Em </ci>
                    <ci> alpha3_E50 </ci>
                  </apply> 
                  <ci> alpha3_Eslope </ci>
                </apply>
              </apply>
            </apply>
          </apply>
        </apply>
      </apply>
      
      <apply id="hyperpolarisation_activated_current_beta3_calculation">
        <eq/>
        <ci> beta3 </ci>
        <apply>
          <plus/>
          <ci> beta3_infinity </ci>
          <apply>
            <divide/>
            <apply>
              <minus/>
              <ci> beta3_0 </ci>
              <ci> beta3_infinity </ci>
            </apply>
            <apply>
              <plus/>
              <cn cellml:units="dimensionless"> 1.0 </cn>
              <apply>
                <exp/>
                <apply>
                  <divide/>
                  <apply>
                    <minus/>
                    <ci> Em </ci>
                    <ci> beta3_E50 </ci>
                  </apply> 
                  <ci> beta3_Eslope </ci>
                </apply>
              </apply>
            </apply>
          </apply>
        </apply>
      </apply>
    </math>
  </component>
  
  <component name="sodium_potassium_pump_current">
    <variable units="picoA" public_interface="out" name="i_NaK"/>
    
    <variable units="millimolar" name="Km_K" initial_value="4.0E1"/>
    <variable units="millimolar" name="Km_Na" initial_value="1.0"/>
    <variable units="picoA" name="Ip_max" initial_value="2.463E2"/>
    
    <variable units="millimolar" public_interface="in" name="Nai"/>
    <variable units="millimolar" public_interface="in" name="Ko"/>
    <variable units="millivolt" public_interface="in" name="Em"/>
    
    <math xmlns="http://www.w3.org/1998/Math/MathML">
      <apply id="i_NaK_calculation">
        <eq/>
        <ci> i_NaK </ci>
        <apply>
          <times/> 
          <ci> Ip_max </ci>
          <apply>
            <divide/>
            <ci> Nai </ci>
            <apply>
              <plus/>
              <ci> Nai </ci>
              <ci> Km_Na </ci>
            </apply>
          </apply>
          <apply>
            <divide/>
            <ci> Ko </ci>
            <apply>
              <plus/>
              <ci> Ko </ci>
              <ci> Km_K </ci>
            </apply>
          </apply>
          <apply>
            <minus/>
            <cn cellml:units="dimensionless"> 1.0 </cn>
            <apply>
              <power/>
              <apply>
                <divide/>
                <apply>
                  <minus/>
                  <ci> Em </ci>
                  <cn cellml:units="millivolt"> 40.0 </cn>
                </apply>
                <cn cellml:units="millivolt"> 211.0 </cn>
              </apply>
              <cn cellml:units="dimensionless"> 2.0 </cn>
            </apply>
          </apply>
        </apply>
      </apply>
    </math>
  </component>
  
  <component name="transient_outward_current">
    <variable units="picoA" public_interface="out" name="i_to"/>
    
    <variable units="nanoS" name="g_to" initial_value="2.818E-1"/>
    <variable units="dimensionless" name="A_to" initial_value="1.220E-2"/>
    <variable units="dimensionless" name="I1" initial_value="6.310E-1"/>
    <variable units="dimensionless" name="I2" initial_value="2.697E-2"/>
    <variable units="dimensionless" name="I3"/>
    <variable units="first_order_rate_constant" name="alpha1"/>
    <variable units="first_order_rate_constant" name="alpha2"/>
    <variable units="first_order_rate_constant" name="alpha3"/>
    <variable units="first_order_rate_constant" name="alpha4"/>
    <variable units="first_order_rate_constant" name="beta1"/>
    <variable units="first_order_rate_constant" name="beta4"/>
    <variable units="first_order_rate_constant" name="alpha1_0" initial_value="3.723"/>
    <variable units="first_order_rate_constant" name="alpha1_infinity" initial_value="3.244E2"/>
    <variable units="millivolt" name="alpha1_E50" initial_value="2.695E1"/>
    <variable units="millivolt" name="alpha1_Eslope" initial_value="1.808E1"/>
    <variable units="first_order_rate_constant" name="alpha2_0" initial_value="3.713E2"/>
    <variable units="first_order_rate_constant" name="alpha2_infinity" initial_value="1.288E2"/>
    <variable units="millivolt" name="alpha2_E50" initial_value="-9.952E1"/>
    <variable units="millivolt" name="alpha2_Eslope" initial_value="1.706E1"/>
    <variable units="first_order_rate_constant" name="alpha3_0" initial_value="4.309"/>
    <variable units="first_order_rate_constant" name="alpha3_infinity" initial_value="3.371E1"/>
    <variable units="millivolt" name="alpha3_E50" initial_value="1.886E1"/>
    <variable units="millivolt" name="alpha3_Eslope" initial_value="1.485E1"/>
    <variable units="first_order_rate_constant" name="alpha4_0" initial_value="1.167E2"/>
    <variable units="first_order_rate_constant" name="alpha4_infinity" initial_value="1.997E2"/>
    <variable units="millivolt" name="alpha4_E50" initial_value="-8.894E1"/>
    <variable units="millivolt" name="alpha4_Eslope" initial_value="8.432E1"/>
    <variable units="first_order_rate_constant" name="beta1_0" initial_value="2.729E-2"/>
    <variable units="first_order_rate_constant" name="beta1_infinity" initial_value="1.451E2"/>
    <variable units="millivolt" name="beta1_E50" initial_value="-1.075E1"/>
    <variable units="millivolt" name="beta1_Eslope" initial_value="5.012"/>
    <variable units="first_order_rate_constant" name="beta4_0" initial_value="2.805E-1"/>
    <variable units="first_order_rate_constant" name="beta4_infinity" initial_value="7.776"/>
    <variable units="millivolt" name="beta4_E50" initial_value="-1.176E2"/>
    <variable units="millivolt" name="beta4_Eslope" initial_value="1.032E2"/>
    
    <variable units="millivolt" public_interface="in" name="E_K"/>
    <variable units="second" public_interface="in" name="time"/>
    <variable units="millivolt" public_interface="in" name="Em"/>
    
    <math xmlns="http://www.w3.org/1998/Math/MathML">
      <apply id="i_to_calculation">
        <eq/>
        <ci> i_to </ci>
        <apply>
          <times/>
          <ci> g_to </ci>
          <ci> A_to </ci>
          <apply>
            <minus/>
            <ci> Em </ci>
            <ci> E_K </ci>
          </apply>
        </apply>
      </apply>
      
      <apply id="dA_to_dt">
        <eq/>
        <apply>
          <diff/>
          <bvar>
            <ci> time </ci>
          </bvar>
          <ci> A_to </ci>
        </apply>
        <apply>
          <minus/>
          <apply>
            <times/>
            <ci> alpha1 </ci>
            <ci> I3 </ci>
          </apply>
          <apply>
            <times/>
            <apply>
              <plus/>
              <ci> beta1 </ci>
              <ci> alpha2 </ci>
            </apply>
            <ci> A_to </ci>
          </apply>
        </apply>
      </apply>
      
      <apply id="transient_outward_current_dI1_dt">
        <eq/>
        <apply>
          <diff/>
          <bvar>
            <ci> time </ci>
          </bvar>
          <ci> I1 </ci>
        </apply>
        <apply>
          <minus/>
          <apply>
            <times/>
            <ci> alpha2 </ci>
            <ci> A_to </ci>
          </apply>
          <apply>
            <times/>
            <ci> alpha3 </ci>
            <ci> I1 </ci>
          </apply>
        </apply>
      </apply>
      
      <apply id="transient_outward_current_dI2_dt">
        <eq/>
        <apply>
          <diff/>
          <bvar>
            <ci> time </ci>
          </bvar>
          <ci> I2 </ci>
        </apply>
        <apply>
          <minus/>
          <apply>
            <plus/>
            <apply>
              <times/>
              <ci> alpha3 </ci>
              <ci> I1 </ci>
            </apply>
            <apply>
              <times/>
              <ci> beta4 </ci>
              <ci> I3 </ci>
            </apply>
          </apply>
          <apply>
            <times/>
            <ci> alpha4 </ci>
            <ci> I2 </ci>
          </apply>
        </apply>
      </apply>
      
      <apply id="transient_outward_current_dI3_dt">
        <eq/>
        <apply>
          <diff/>
          <bvar>
            <ci> time </ci>
          </bvar>
          <ci> I3 </ci>
        </apply>
        <apply>
          <minus/>
          <apply>
            <plus/>
            <apply>
              <times/>
              <ci> beta1 </ci>
              <ci> A_to </ci>
            </apply>
            <apply>
              <times/>
              <ci> alpha4 </ci>
              <ci> I2 </ci>
            </apply>
          </apply>
          <apply>
            <times/>
            <apply>
              <plus/>
              <ci> alpha1 </ci>
              <ci> beta4 </ci>
            </apply>
            <ci> I3 </ci>
          </apply>
        </apply>
      </apply>
      
      <apply id="transient_outward_current_alpha1_calculation">
        <eq/>
        <ci> alpha1 </ci>
        <apply>
          <plus/>
          <ci> alpha1_infinity </ci>
          <apply>
            <divide/>
            <apply>
              <minus/>
              <ci> alpha1_0 </ci>
              <ci> alpha1_infinity </ci>
            </apply>
            <apply>
              <plus/>
              <cn cellml:units="dimensionless"> 1.0 </cn>
              <apply>
                <exp/>
                <apply>
                  <divide/>
                  <apply>
                    <minus/>
                    <ci> Em </ci>
                    <ci> alpha1_E50 </ci>
                  </apply> 
                  <ci> alpha1_Eslope </ci>
                </apply>
              </apply>
            </apply>
          </apply>
        </apply>
      </apply>
      
      <apply id="transient_outward_current_beta1_calculation">
        <eq/>
        <ci> beta1 </ci>
        <apply>
          <plus/>
          <ci> beta1_infinity </ci>
          <apply>
            <divide/>
            <apply>
              <minus/>
              <ci> beta1_0 </ci>
              <ci> beta1_infinity </ci>
            </apply>
            <apply>
              <plus/>
              <cn cellml:units="dimensionless"> 1.0 </cn>
              <apply>
                <exp/>
                <apply>
                  <divide/>
                  <apply>
                    <minus/>
                    <ci> Em </ci>
                    <ci> beta1_E50 </ci>
                  </apply> 
                  <ci> beta1_Eslope </ci>
                </apply>
              </apply>
            </apply>
          </apply>
        </apply>
      </apply>
      
      <apply id="transient_outward_current_alpha2_calculation">
        <eq/>
        <ci> alpha2 </ci>
        <apply>
          <plus/>
          <ci> alpha2_infinity </ci>
          <apply>
            <divide/>
            <apply>
              <minus/>
              <ci> alpha2_0 </ci>
              <ci> alpha2_infinity </ci>
            </apply>
            <apply>
              <plus/>
              <cn cellml:units="dimensionless"> 1.0 </cn>
              <apply>
                <exp/>
                <apply>
                  <divide/>
                  <apply>
                    <minus/>
                    <ci> Em </ci>
                    <ci> alpha2_E50 </ci>
                  </apply> 
                  <ci> alpha2_Eslope </ci>
                </apply>
              </apply>
            </apply>
          </apply>
        </apply>
      </apply>
      
      <apply id="transient_outward_current_alpha3_calculation">
        <eq/>
        <ci> alpha3 </ci>
        <apply>
          <plus/>
          <ci> alpha3_infinity </ci>
          <apply>
            <divide/>
            <apply>
              <minus/>
              <ci> alpha3_0 </ci>
              <ci> alpha3_infinity </ci>
            </apply>
            <apply>
              <plus/>
              <cn cellml:units="dimensionless"> 1.0 </cn>
              <apply>
                <exp/>
                <apply>
                  <divide/>
                  <apply>
                    <minus/>
                    <ci> Em </ci>
                    <ci> alpha3_E50 </ci>
                  </apply> 
                  <ci> alpha3_Eslope </ci>
                </apply>
              </apply>
            </apply>
          </apply>
        </apply>
      </apply>
      
      <apply id="transient_outward_current_alpha4_calculation">
        <eq/>
        <ci> alpha4 </ci>
        <apply>
          <plus/>
          <ci> alpha4_infinity </ci>
          <apply>
            <divide/>
            <apply>
              <minus/>
              <ci> alpha4_0 </ci>
              <ci> alpha4_infinity </ci>
            </apply>
            <apply>
              <plus/>
              <cn cellml:units="dimensionless"> 1.0 </cn>
              <apply>
                <exp/>
                <apply>
                  <divide/>
                  <apply>
                    <minus/>
                    <ci> Em </ci>
                    <ci> alpha4_E50 </ci>
                  </apply> 
                  <ci> alpha4_Eslope </ci>
                </apply>
              </apply>
            </apply>
          </apply>
        </apply>
      </apply>
      
      <apply id="transient_outward_current_beta4_calculation">
        <eq/>
        <ci> beta4 </ci>
        <apply>
          <plus/>
          <ci> beta4_infinity </ci>
          <apply>
            <divide/>
            <apply>
              <minus/>
              <ci> beta4_0 </ci>
              <ci> beta4_infinity </ci>
            </apply>
            <apply>
              <plus/>
              <cn cellml:units="dimensionless"> 1.0 </cn>
              <apply>
                <exp/>
                <apply>
                  <divide/>
                  <apply>
                    <minus/>
                    <ci> Em </ci>
                    <ci> beta4_E50 </ci>
                  </apply> 
                  <ci> beta4_Eslope </ci>
                </apply>
              </apply>
            </apply>
          </apply>
        </apply>
      </apply>
    </math>
  </component>
  
  <component name="background_currents">
    <variable units="picoA" public_interface="out" name="i_bNa"/>
    <variable units="picoA" public_interface="out" name="i_bCl"/>
    <variable units="picoA" public_interface="out" name="i_bK"/>

    <variable units="nanoS" name="g_bCl" initial_value="8.691E-2"/>
    <variable units="dimensionless" name="Kb_K"/>
    
    <variable units="millivolt" public_interface="in" name="E_Cl"/>
    <variable units="nanoS" public_interface="in" name="g_Na"/>
    <variable units="millivolt" public_interface="in" name="E_Na"/>
    <variable units="millivolt" public_interface="in" name="Em"/>
    <variable units="joule_per_mole_kelvin" public_interface="in" name="R"/>
    <variable units="kelvin" public_interface="in" name="T"/>
    <variable units="coulomb_per_mole" public_interface="in" name="F"/>
    <variable units="millimolar" public_interface="in" name="Ki"/>
    <variable units="millimolar" public_interface="in" name="Ko"/>
    
    <math xmlns="http://www.w3.org/1998/Math/MathML">
      <apply id="i_bNa_calculation">
        <eq/>
        <ci> i_bNa </ci>
        <apply>
          <times/>
          <ci> g_Na </ci>
          <apply>
            <minus/>
            <ci> Em </ci>
            <ci> E_Na </ci>
          </apply>
        </apply>
      </apply>
      
      <apply id="i_bK_calculation">
        <eq/>
        <ci> i_bK </ci>
        <apply>
          <times/>
          <ci> Kb_K </ci>
          <apply>
            <power/>
            <ci> Ko </ci>
            <cn cellml:units="dimensionless"> 0.41 </cn>
          </apply>
          <apply>
            <minus/>
            <ci> Ki </ci>
            <apply>
              <times/>
              <ci> Ko </ci>
              <apply>
                <exp/>
                <apply>
                  <minus/>
                  <apply>
                    <divide/>
                    <apply>
                      <times/>
                      <ci> Em </ci>
                      <ci> F </ci>
                    </apply>
                    <apply>
                      <times/>
                      <ci> R </ci>
                      <ci> T </ci>
                    </apply>
                  </apply>
                </apply>
              </apply>
            </apply>
          </apply>
        </apply>
      </apply>
      
      <apply id="i_bCl_calculation">
        <eq/>
        <ci> i_bCl </ci>
        <apply>
          <times/>
          <ci> g_bCl </ci>
          <apply>
            <minus/>
            <ci> Em </ci>
            <ci> E_Cl </ci>
          </apply>
        </apply>
      </apply>
    </math>
  </component>
  
  <component name="calcium_dynamics">
    <variable units="picoA" public_interface="out" name="i_Ca_up"/>
    <variable units="picoA" public_interface="out" name="i_Ca_rel"/>
    <variable units="picoA" public_interface="out" name="i_Ca_tr"/>
      
    <variable units="picoA" name="Iup_max" initial_value="2.120E1"/>
    <variable units="millimolar" name="Km_Caup" initial_value="5.000E-4"/>
    <variable units="millimolar" name="Km_Carel" initial_value="1.000E-3"/>
    <variable units="second" name="tau_rel" initial_value="5.000E-3"/>
    <variable units="second" name="tau_tr" initial_value="4.000E-1"/>
    
    <variable units="picol" public_interface="in" name="Vrel"/>
    <variable units="second" public_interface="in" name="time"/>
    <variable units="coulomb_per_mole" public_interface="in" name="F"/>
    <variable units="millimolar" public_interface="in" name="Cai"/>
    <variable units="millimolar" public_interface="in" name="Carel"/>
    <variable units="millimolar" public_interface="in" name="Caup"/>
    
    <math xmlns="http://www.w3.org/1998/Math/MathML">
      <apply id="i_Ca_up_calculation">
        <eq/>
        <ci> i_Ca_up </ci>
        <apply>
          <times/>
          <ci> Iup_max </ci>
          <apply>
            <divide/>
            <cn cellml:units="dimensionless"> 1.0 </cn>
            <apply>
              <plus/>
              <cn cellml:units="dimensionless"> 1.0 </cn>
              <apply>
                <power/>
                <apply>
                  <divide/>
                  <ci> Km_Caup </ci>
                  <ci> Cai </ci>
                </apply>
                <cn cellml:units="dimensionless"> 2.0 </cn>
              </apply>
            </apply>
          </apply>
        </apply>
      </apply>
      
      <apply id="i_Ca_rel_calculation">
        <eq/>
        <ci> i_Ca_rel </ci>
        <apply>
          <times/>
          <apply>
            <divide/>
            <apply>
              <times/>
              <cn cellml:units="dimensionless"> 2.0 </cn>
              <ci> F </ci>
              <ci> Vrel </ci>
            </apply>
            <ci> tau_rel </ci>
          </apply>
          <ci> Carel </ci>
          <apply>
            <divide/>
            <cn cellml:units="dimensionless"> 1.0 </cn>
            <apply>
              <plus/>
              <cn cellml:units="dimensionless"> 1.0 </cn>
              <apply>
                <power/>
                <apply>
                  <divide/>
                  <ci> Km_Carel </ci>
                  <ci> Cai </ci>
                </apply>
                <cn cellml:units="dimensionless"> 2.0 </cn>
              </apply>
            </apply>
          </apply>
        </apply>
      </apply>
      
      <apply id="i_Ca_tr_calculation">
        <eq/>
        <ci> i_Ca_tr </ci>
        <apply>
          <times/>
          <apply>
            <divide/>
            <apply>
              <times/>
              <cn cellml:units="dimensionless"> 2.0 </cn>
              <ci> F </ci>
              <ci> Vrel </ci>
            </apply>
            <ci> tau_tr </ci>
          </apply>
          <ci> Caup </ci>
        </apply>
      </apply>
    </math>
  </component>
  
  <component name="ion_concentrations">
    <variable units="millimolar" public_interface="out" name="Cai" initial_value="1.275E-4"/>
    <variable units="millimolar" public_interface="out" name="Cao" initial_value="2.0"/>
    <variable units="millimolar" public_interface="out" name="Caup" initial_value="1.035"/>
    <variable units="millimolar" public_interface="out" name="Carel" initial_value="2.448E-1"/>
    <variable units="millimolar" public_interface="out" name="Nai" initial_value="8.004"/>
    <variable units="millimolar" public_interface="out" name="Nao" initial_value="1.400E2"/>
    <variable units="millimolar" public_interface="out" name="Ki" initial_value="1.499E2"/>
    <variable units="millimolar" public_interface="out" name="Ko" initial_value="5.389"/>
    <variable units="millimolar" public_interface="out" name="Cli" initial_value="2.607E1"/>
    <variable units="millimolar" public_interface="out" name="Clo" initial_value="1.400E2"/>
    <variable units="picol" public_interface="out" name="Vrel" initial_value="1.5E-2"/>
    
    <variable units="second" name="tau_b" initial_value="1.0E-1"/>
    <variable units="millimolar" name="Cab" initial_value="2.0"/>
    <variable units="millimolar" name="Clb" initial_value="1.4E2"/>
    <variable units="millimolar" name="Kb" initial_value="5.4"/>
    <variable units="millimolar" name="Nab" initial_value="1.4E2"/>
    <variable units="picol" name="Vi" initial_value="2.5"/>
    <variable units="picol" name="Vup" initial_value="3.5E-2"/>
    <variable units="picol" name="Ve" initial_value="5.0E-1"/>
     
    <variable units="second" public_interface="in" name="time"/>
    <variable units="coulomb_per_mole" public_interface="in" name="F"/>
    <variable units="picoA" public_interface="in" name="i_bNa"/>
    <variable units="picoA" public_interface="in" name="i_bK"/>
    <variable units="picoA" public_interface="in" name="i_fNa"/>
    <variable units="picoA" public_interface="in" name="i_fK"/>
    <variable units="picoA" public_interface="in" name="i_bCl"/>
    <variable units="picoA" public_interface="in" name="i_CaL"/>
    <variable units="picoA" public_interface="in" name="i_CaT"/>
    <variable units="picoA" public_interface="in" name="i_NaCa"/>
    <variable units="picoA" public_interface="in" name="i_Ca_rel"/>
    <variable units="picoA" public_interface="in" name="i_Ca_tr"/>
    <variable units="picoA" public_interface="in" name="i_Ca_up"/>
    <variable units="picoA" public_interface="in" name="i_NaK"/>
    <variable units="picoA" public_interface="in" name="i_Na"/>
    <variable units="picoA" public_interface="in" name="i_Kr_Na"/>
    <variable units="picoA" public_interface="in" name="i_Ks_Na"/>
    <variable units="picoA" public_interface="in" name="i_Kr_K"/>
    <variable units="picoA" public_interface="in" name="i_Ks_K"/>
    <variable units="picoA" public_interface="in" name="i_to"/>
     
    <math xmlns="http://www.w3.org/1998/Math/MathML">
      <apply id="dCai_dt">
        <eq/>
        <apply>
          <diff/>
          <bvar>
            <ci> time </ci>
          </bvar>
          <ci> Cai </ci>
        </apply>
        <apply>
          <minus/>
          <apply>
            <divide/>
            <apply>
              <minus/>
              <apply>
                <plus/>
                <ci> i_CaL </ci>
                <ci> i_CaT </ci>
                <ci> i_Ca_up </ci>
              </apply>
              <apply>
                <plus/>
                <apply>
                  <times/>
                  <cn cellml:units="dimensionless"> 2.0 </cn>
                  <ci> i_NaCa </ci>
                </apply>
                <ci> i_Ca_rel </ci>
              </apply>
            </apply>
            <apply>
              <times/>
              <cn cellml:units="dimensionless"> 2.0 </cn>
              <ci> F </ci>
              <ci> Vi </ci>
            </apply>
          </apply>
        </apply>
      </apply>
      
      <apply id="dCaup_dt">
        <eq/>
        <apply>
          <diff/>
          <bvar>
            <ci> time </ci>
          </bvar>
          <ci> Caup </ci>
        </apply>
        <apply>
          <divide/>
          <apply>
            <minus/>
            <ci> i_Ca_up </ci>
            <ci> i_Ca_tr </ci>
          </apply>
          <apply>
            <times/>
            <cn cellml:units="dimensionless"> 2.0 </cn>
            <ci> F </ci>
            <ci> Vup </ci>
          </apply>
        </apply>
      </apply>
      
      <apply id="dCarel_dt">
        <eq/>
        <apply>
          <diff/>
          <bvar>
            <ci> time </ci>
          </bvar>
          <ci> Carel </ci>
        </apply>
        <apply>
          <divide/>
          <apply>
            <minus/>
            <ci> i_Ca_tr </ci>
            <ci> i_Ca_rel </ci>
          </apply>
          <apply>
            <times/>
            <cn cellml:units="dimensionless"> 2.0 </cn>
            <ci> F </ci>
            <ci> Vrel </ci>
          </apply>
        </apply>
      </apply>
      
      <apply id="dCao_dt">
        <eq/>
        <apply>
          <diff/>
          <bvar>
            <ci> time </ci>
          </bvar>
          <ci> Cao </ci>
        </apply>
        <apply>
          <plus/>
          <apply>
            <divide/>
            <apply>
              <minus/>
              <apply>
                <plus/>
                <ci> i_CaL </ci>
                <ci> i_CaT </ci>
              </apply>
              <apply>
                <times/>
                <cn cellml:units="dimensionless"> 2.0 </cn>
                <ci> i_NaCa </ci>
              </apply>
            </apply>
            <apply>
              <times/>
              <cn cellml:units="dimensionless"> 2.0 </cn>
              <ci> F </ci>
              <ci> Ve </ci>
            </apply>
          </apply>
          <apply>
            <divide/>
            <apply>
              <minus/>
              <ci> Cab </ci>
              <ci> Cao </ci>
            </apply>
            <ci> tau_b </ci>
          </apply>
        </apply>
      </apply>
      
      <apply id="dNai_dt">
        <eq/>
        <apply>
          <diff/>
          <bvar>
            <ci> time </ci>
          </bvar>
          <ci> Nai </ci>
        </apply>
        <apply>
          <minus/>
          <apply>
            <divide/>
            <apply>
              <plus/>
              <ci> i_Kr_Na </ci>
              <ci> i_Ks_Na </ci>
              <ci> i_Na </ci>
              <apply>
                <times/>
                <cn cellml:units="dimensionless"> 3.0 </cn>
                <ci> i_NaCa </ci>
              </apply>
              <ci> i_bNa </ci>
              <ci> i_fNa </ci>
              <apply>
                <times/>
                <cn cellml:units="dimensionless"> 3.0 </cn>
                <ci> i_NaK </ci>
              </apply>
            </apply>
            <apply>
              <times/>
              <ci> F </ci>
              <ci> Vi </ci>
            </apply>
          </apply>
        </apply>
      </apply>
      
      <apply id="dNao_dt">
        <eq/>
        <apply>
          <diff/>
          <bvar>
            <ci> time </ci>
          </bvar>
          <ci> Nao </ci>
        </apply>
        <apply>
          <plus/>
          <apply>
            <divide/>
            <apply>
              <plus/>
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