Location: Vangoor, Lebeau, Krsmanovic, Sherman, Catt, Stojilkovic, 2000 @ dee10f15d0ea / vangoor_lebeau_krsmanovic_sherman_catt_stojilkovic_2000.cellml

Author:
pmr2.import <nobody@models.cellml.org>
Date:
2009-06-17 16:17:31+12:00
Desc:
committing version02 of vangoor_lebeau_krsmanovic_sherman_catt_stojilkovic_2000
Permanent Source URI:
https://models.physiomeproject.org/workspace/vangoor_lebeau_krsmanovic_sherman_catt_stojilkovic_2000/rawfile/dee10f15d0ea20c65e24d1cd5b8c67fb538bc400/vangoor_lebeau_krsmanovic_sherman_catt_stojilkovic_2000.cellml

<?xml version='1.0' encoding='utf-8'?>
<!--  FILE :  vangoor_model_2000_version02.xml

CREATED :  28th May 2007

LAST MODIFIED : 28th May 2007

AUTHOR :  Catherine Lloyd
          Bioengineering Institute
          The University of Auckland
          
MODEL STATUS :  This model conforms to the CellML 1.1 Specification.

DESCRIPTION :  This file contains a CellML description of Van Goor et al's
2000 mathematical model of amplitude-dependent spike broadening and enhanced Ca2+ signaling in GnRH-secreting neurons.

CHANGES:  
  
--><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="vangoor_model_2000_version02" name="vangoor_lebeau_krsmanovic_sherman_catt_stojilkovic_2000_version01">
<documentation xmlns="http://cellml.org/tmp-documentation">
<article>
  <articleinfo>
  <title>Amplitude-Dependent Spike-Broadening In GnRH-Secreting Neurons</title>
  <author>
    <firstname>Catherine</firstname>
          <surname>Lloyd</surname>
    <affiliation>
      <shortaffil>Bioengineering Institute, University of Auckland</shortaffil>
    </affiliation>
  </author>
</articleinfo>
  <sect1 id="sec_structure">
<title>Model Structure</title>

<para>
During an action potential, depolarisation of the plasma membrane causes voltage-gated Ca<superscript>2+</superscript> channels to open, allowing Ca<superscript>2+</superscript> to diffuse into the cell.  The subsequent increase in cytosolic calcium concentration ([Ca<superscript>2+</superscript>]<subscript>i</subscript>) triggers a number of biochemical events involved in the control of cell function.  The frequency, amplitude and duration of the Ca<superscript>2+</superscript> signals determine the specificity of the cellular response.  However, the exact relationship between the action potential waveform, the gating properties of the voltage-gated Ca<superscript>2+</superscript> channels, the pattern of Ca<superscript>2+</superscript> influx and the ionic mechanisms underlying the the agonist-induced Ca<superscript>2+</superscript> spike broadening has not been characterised. </para>

<para>  
In their 2000 paper, Fredrick Van Goor, Andrew P. LeBeau, Lazar Z. Krsmanovic, Arthur Sherman, Kevin J. Catt and Stanko S. Stojikovic examine the ionic mechanism mediating depolarisation-induced Ca<superscript>2+</superscript> spike broadening in GnRH-secreting (GT1) neurons.  The validity of their experimental results were tested by comparing them with a computational model.  They also used this mathematical model to examine the influence of voltage-gated Ca<superscript>2+</superscript> channel gating properties on the ability of action potential broadening to enhance the I<subscript>Ca</subscript>.
</para>

<para>
Their mathematical model is based exclusively on the on the properties of the individual ionic currents characterised in GT1 neurons.  The ionic currents used were a TTX-sensitive I<subscript>Na</subscript>, L- and T-type I<subscript>Ca</subscript>, a voltage sensitive (delayed-rectifying) I<subscript>K(dr)</subscript>, an M-like I<subscript>K</subscript> (I<subscript>M</subscript>), an inward rectifier I<subscript>K</subscript> (I<subscript>ir</subscript>), and a Ca<superscript>2+</superscript> permeable, voltage-insensitive inward leak, I<subscript>d</subscript> (see figure 1 below).
</para>


<para>
In their original model, Van Goor <emphasis>et al</emphasis>. used a Hodgkin-Huxley type equation to represent the sodium current.  However, in this description, I<subscript>Na</subscript> exhibited a large surge of activation during the spike repolarisation, and it also did not spike during broadening, suggesting that the model gating kinetics didn't accurately represent those in GTI neurons.  Consequently, they replaced the Hodgkin-Huxley-like description with Kuo and Bean's 1994 model of I<subscript>Na</subscript> (see figure 2 below).  In this description the Na+ channel is composed of subunits with four possible states: deactivated (D), activated (A), deactivated-inhibited (D*), and activated-inhibited (A*).  The open, conducting state (O) is given by A3 in the reaction scheme.
</para>

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

<para>
<ulink url="http://www.biophysj.org/cgi/content/abstract/79/3/1310">Amplitude-Dependent Spike-Broadening and Enhanced Ca<superscript>2+</superscript> Signaling in GnRH-Secreting Neurons</ulink>, Fredrick Van Goor, Andrew P. LeBeau, Lazar Z. Krsmanovic, Arthur Sherman, Kevin J. Catt and Stanko S. Stojikovic, 2000, <ulink url="http://www.biophysj.org/">
            <emphasis>Biophysical Journal</emphasis>
          </ulink>, 79, 1310-1323.  (<ulink url="http://www.biophysj.org/cgi/content/full/79/3/1310">Full text</ulink> and <ulink url="http://www.biophysj.org/cgi/reprint/79/3/1310.pdf">PDF</ulink> versions of the article are available for Journal Members on the BJ website.)  <ulink url="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&amp;db=PubMed&amp;list_uids=10968994&amp;dopt=Abstract">PubMed ID: 10968994</ulink> 
</para>


<informalfigure float="0" id="fig_cell_diagram">
<mediaobject>
  <imageobject>
    <objectinfo>
      <title>diagram of the cell model</title>
    </objectinfo>
    <imagedata fileref="vangoor_2000-celldiagram.png"/>
  </imageobject>
</mediaobject>
</informalfigure>

<informalfigure float="0" id="fig_reaction_diagram">
<mediaobject>
  <imageobject>
    <objectinfo>
      <title>diagram of the cell model</title>
    </objectinfo>
    <imagedata fileref="vangoor_2000.png"/>
  </imageobject>
</mediaobject>
</informalfigure>

</sect1>
</article>
</documentation>


  
  
  
  <units name="millisecond">
    <unit units="second" prefix="milli"/>
  </units>
  
  <units name="first_order_rate_constant">
    <unit units="millisecond" exponent="-1"/>
  </units>
  
  <units name="millivolt">
    <unit units="volt" prefix="milli"/>
  </units>
  
  <units name="picoF">
    <unit units="farad" prefix="pico"/>
  </units>
  
  <units name="picoA">
    <unit units="ampere" prefix="pico"/>
  </units>
  
  <units name="nanoS">
    <unit units="siemens" prefix="nano"/>
  </units>
  
  <units name="millimolar">
    <unit units="mole" prefix="milli"/>
    <unit units="litre" exponent="-1"/>
  </units>
  
  <units name="second_order_rate_constant">
    <unit units="millimolar"/>
    <unit units="millisecond" exponent="-1"/>
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  <component name="environment">
    <variable units="millisecond" public_interface="out" name="time"/>
  </component>
  
  <component name="membrane">
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    <variable units="picoF" name="Cm" initial_value="14.0"/>
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    <variable units="millisecond" public_interface="in" name="time"/>
    <variable units="picoA" public_interface="in" name="i_Na"/>
    <variable units="picoA" public_interface="in" name="i_Ca_L"/>
    <variable units="picoA" public_interface="in" name="i_Ca_T"/>
    <variable units="picoA" public_interface="in" name="i_K_dr"/>
    <variable units="picoA" public_interface="in" name="i_M"/>
    <variable units="picoA" public_interface="in" name="i_ir"/>
    <variable units="picoA" public_interface="in" name="i_d"/>
    
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            <apply>
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              <ci> i_Ca_L </ci>
              <ci> i_Ca_T </ci>
              <ci> i_K_dr </ci>
              <ci> i_M </ci>
              <ci> i_ir </ci>
              <ci> i_d </ci>
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          </apply>
          <ci> Cm </ci>
        </apply>
      </apply>
    </math>
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    <rdf:Description rdf:about="#sodium_current">
      <cmeta:comment rdf:parseType="Resource">
        <rdf:value>
          In their original model, Van Goor et al. used a Hodgkin-Huxley type 
          equation to represent the sodium current (see CellML description 
          below).  However, in this description, INa exhibited a large surge of 
          activation during the spike repolarisation, and also did not spike 
          during broadening, suggesting that the model gating kinetics don't 
          accurately represent those in GTI neurons.  
          
          Consequently, they replaced the Hodgkin-Huxley-like description with 
          Kuo and Bean's 1994 model of INa.  In this description the Na+ channel 
          is composed of subunits with four possible states: deactivated (D), 
          activated (A), deactivated-inhibited (D*), and activated-inhibited 
          (A*).  The open, conducting state (O) is given by A3 in the reaction 
          scheme.
      
          Following is the original reaction scheme. 
        </rdf:value>
        
        <rdf:value rdf:parseType="Literal">
          <component name="sodium_current">
            <variable units="picoA" public_interface="out" name="i_Na"/>

            <variable units="nanoS" name="g_Na" initial_value="60.0"/>
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            <variable units="dimensionless" private_interface="in" name="h"/>

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                  <ci> g_Na </ci>
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                    <ci> m </ci>
                    <cn cellml:units="dimensionless"> 3.0 </cn>
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                    <ci> V </ci>
                    <ci> V_Na </ci>
                  </apply>
                </apply>
              </apply>
            </math>
          </component>

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            <variable units="dimensionless" public_interface="out" name="m"/>

            <variable units="dimensionless" name="m_infinity"/>
            <variable units="millisecond" name="tau_m"/>

            <variable units="millivolt" public_interface="in" name="V"/>
            <variable units="millisecond" public_interface="in" name="time"/>

            <math xmlns="http://www.w3.org/1998/Math/MathML">
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                    <ci> m </ci>
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                  <ci> tau_m </ci>
                </apply>
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                        <cn cellml:units="millivolt"> 4.3 </cn>
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                          <cn cellml:units="millivolt"> 11.0 </cn>
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                        <cn cellml:units="dimensionless"> 2.0 </cn>
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                              <cn cellml:units="dimensionless"> -2.0 </cn>
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                                <ci> V </ci>
                                <cn cellml:units="millivolt"> 47.0 </cn>
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                            <cn cellml:units="millivolt"> 11.0 </cn>
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                  </apply>
                  <cn cellml:units="millisecond"> 0.1 </cn>
                </apply>
              </apply>
            </math>
          </component>

          <component name="sodium_current_h_gate">
            <variable units="dimensionless" public_interface="out" name="h"/>

            <variable units="dimensionless" name="h_infinity"/>
            <variable units="millisecond" name="tau_h"/>

            <variable units="millivolt" public_interface="in" name="V"/>
            <variable units="millisecond" public_interface="in" name="time"/>

            <math xmlns="http://www.w3.org/1998/Math/MathML">
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                    <cn cellml:units="dimensionless"> 1.0 </cn>
                    <apply>
                      <exp/>
                      <apply>
                        <divide/>
                        <apply>
                          <plus/>
                          <ci> V </ci>
                          <cn cellml:units="millivolt"> 68.2 </cn>
                        </apply>
                        <cn cellml:units="millivolt"> 10.8 </cn>
                      </apply>
                    </apply>    
                  </apply>
                </apply>
              </apply>

              <apply id="tau_h_calculation">
                <eq/>
                <ci> tau_h </ci>
                <apply>
                  <divide/>
                  <cn cellml:units="millisecond"> 150.0 </cn>
                  <apply>
                    <plus/>
                    <apply>
                      <exp/>
                      <apply>
                        <divide/>
                        <apply>
                          <plus/>
                          <ci> V </ci>
                          <cn cellml:units="millivolt"> 80.0 </cn>
                        </apply>
                        <cn cellml:units="millivolt"> 19.0 </cn>
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                      <cn cellml:units="dimensionless"> 2.0 </cn>
                      <apply>
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                          <cn cellml:units="millivolt"> 19.0 </cn>
                        </apply>
                      </apply>
                    </apply>
                  </apply>
                </apply>
              </apply>
            </math>
          </component>
   
        </rdf:value>
        <!-- The creator of the comment. -->
        <dc:creator rdf:parseType="Resource">
          <vCard:FN>Catherine Lloyd</vCard:FN>
        </dc:creator>
      </cmeta:comment>
    </rdf:Description>
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  <component name="sodium_current">
    <variable units="picoA" public_interface="out" name="i_Na"/>
    
    <variable units="nanoS" name="g_Na" initial_value="60.0"/>
    <variable units="millivolt" name="V_Na" initial_value="60.0"/>
    <variable units="dimensionless" name="O"/>
    
    <variable units="millisecond" public_interface="in" name="time"/>
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    <variable units="millimolar" public_interface="in" name="A"/>
    
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            <ci> V_Na </ci>
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        </apply>
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        <ci> O </ci>
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    <variable units="first_order_rate_constant" public_interface="in" name="alpha"/>
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              <times/>
              <ci> k2 </ci>
              <ci> D </ci>
            </apply>
          </apply>
          <apply>
            <plus/>
            <apply>
              <times/>
              <ci> alpha </ci>
              <ci> a </ci>
              <ci> D_ </ci>
            </apply>
            <apply>
              <times/>
              <ci> k2_ </ci>
              <ci> D_ </ci>
            </apply>
          </apply>
        </apply>  
      </apply> 
    </math> 
  </component>
  
  <component name="reaction_constants">
    <variable units="first_order_rate_constant" public_interface="out" name="k1" initial_value="0.3"/>
    <variable units="first_order_rate_constant" public_interface="out" name="k1_" initial_value="0.03"/>
    <variable units="first_order_rate_constant" public_interface="out" name="k2" initial_value="0.001"/>
    <variable units="first_order_rate_constant" public_interface="out" name="k2_" initial_value="0.01"/>
    <variable units="dimensionless" public_interface="out" name="alpha"/>
    <variable units="dimensionless" public_interface="out" name="beta"/>
    <variable units="dimensionless" public_interface="out" name="a"/>
    
    <variable units="millivolt" public_interface="in" name="V"/>

    <math xmlns="http://www.w3.org/1998/Math/MathML">
      <apply id="alpha_calculation">
        <eq/>
        <ci> alpha </ci>
        <apply>
          <divide/>
          <cn cellml:units="millisecond"> 10.0 </cn>
          <apply>
            <plus/>
            <cn cellml:units="dimensionless"> 1.0 </cn>
            <apply>
              <exp/>
              <apply>
                <divide/>
                <apply>
                  <minus/>
                  <apply>
                    <plus/>
                    <ci> V </ci>
                    <cn cellml:units="millivolt"> 6.0 </cn>
                  </apply>
                </apply>
                <cn cellml:units="millivolt"> 10.0 </cn>
              </apply>
            </apply>    
          </apply>
        </apply>
      </apply>
      
      <apply id="beta_calculation">
        <eq/>
        <ci> beta </ci>
        <apply>
          <divide/>
          <cn cellml:units="millisecond"> 10.0 </cn>
          <apply>
            <plus/>
            <cn cellml:units="dimensionless"> 1.0 </cn>
            <apply>
              <exp/>
              <apply>
                <divide/>
                <apply>
                  <plus/>
                  <ci> V </ci>
                  <cn cellml:units="millivolt"> 54.4 </cn>
                </apply>
                <cn cellml:units="millivolt"> 4.6 </cn>
              </apply>
            </apply>    
          </apply>
        </apply>
      </apply>
      
      <apply id="a_calculation">
        <eq/>
        <ci> a </ci>
        <apply>
          <power/>
          <apply>
            <divide/>
            <apply>
              <times/>
              <ci> k1 </ci>
              <ci> k2_ </ci>
            </apply>
            <apply>
              <times/>
              <ci> k1_ </ci>
              <ci> k2 </ci>
            </apply>
          </apply>
          <cn cellml:units="dimensionless"> 0.5 </cn>
        </apply>
      </apply>
    </math>
  </component>
  
  <component name="L_type_calcium_current">
    <variable units="picoA" public_interface="out" name="i_Ca_L"/>
    <variable units="millivolt" public_interface="out" name="V_Ca" initial_value="100.0"/>
    
    <variable units="nanoS" name="g_Ca_L" initial_value="1.3"/>
    
    <variable units="millisecond" public_interface="in" private_interface="out" name="time"/>
    <variable units="millivolt" public_interface="in" private_interface="out" name="V"/>
    
    <variable units="dimensionless" private_interface="in" name="m"/>
    
    <math xmlns="http://www.w3.org/1998/Math/MathML">
      <apply id="i_Ca_L_calculation">
        <eq/>
        <ci> i_Ca_L </ci>
        <apply>
          <times/>
          <ci> g_Ca_L </ci>
          <apply>
            <power/>
            <ci> m </ci>
            <cn cellml:units="dimensionless"> 2.0 </cn>
          </apply>
          <apply>
            <minus/>
            <ci> V </ci>
            <ci> V_Ca </ci>
          </apply>
        </apply>
      </apply>
    </math>
  </component>
  
  <component name="L_type_calcium_current_m_gate">
    <variable units="dimensionless" public_interface="out" name="m"/>
    
    <variable units="dimensionless" name="m_infinity"/>
    <variable units="millisecond" name="tau_m"/>
    <variable units="millivolt" name="Vh" initial_value="40.0"/>
    
    <variable units="millivolt" public_interface="in" name="V"/>
    <variable units="millisecond" public_interface="in" name="time"/>
   
    <math xmlns="http://www.w3.org/1998/Math/MathML">
      <apply id="L_type_calcium_current_m_gate_m_diff_eq">
        <eq/>
        <apply>
          <diff/>
          <bvar>
            <ci> time </ci>
          </bvar>
          <ci> m </ci>
        </apply>
        <apply>
          <divide/>
          <apply>
            <minus/>
            <ci> m_infinity </ci>
            <ci> m </ci>
          </apply>
          <ci> tau_m </ci>
        </apply>
      </apply>
      
      <apply id="L_type_calcium_current_m_gate_m_infinity_calculation">
        <eq/>
        <ci> m_infinity </ci>
        <apply>
          <divide/>
          <cn cellml:units="dimensionless"> 1.0 </cn>
          <apply>
            <plus/>
            <cn cellml:units="dimensionless"> 1.0 </cn>
            <apply>
              <exp/>
              <apply>
                <divide/>
                <apply>
                  <minus/>
                  <apply>
                    <minus/>
                    <ci> V </ci>
                    <ci> Vh </ci>
                  </apply>
                </apply>
                <cn cellml:units="millivolt"> 12.0 </cn>
              </apply>
            </apply>    
          </apply>
        </apply>
      </apply>
      
      <apply id="L_type_calcium_current_m_gate_tau_m_calculation">
        <eq/>
        <ci> tau_m </ci>
        <apply>
          <divide/>
          <cn cellml:units="millisecond"> 5.0 </cn>
          <apply>
            <plus/>
            <apply>
              <exp/>
              <apply>
                <divide/>
                <apply>
                  <plus/>
                  <ci> V </ci>
                  <cn cellml:units="millivolt"> 15.0 </cn>
                </apply>
                <cn cellml:units="millivolt"> 25.0 </cn>
              </apply>
            </apply>
            <apply>
              <exp/>
              <apply>
                <divide/>
                <apply>
                  <minus/>
                  <apply>
                    <plus/>
                    <ci> V </ci>
                    <cn cellml:units="millivolt"> 15.0 </cn>
                  </apply>
                </apply>
                <cn cellml:units="millivolt"> 25.0 </cn>
              </apply>
            </apply>
          </apply>
        </apply>
      </apply>
    </math>
  </component>
  
  <component name="T_type_calcium_current">
    <variable units="picoA" public_interface="out" name="i_Ca_T"/>
     
    <variable units="nanoS" name="g_Ca_T" initial_value="0.94"/>
    
    <variable units="millisecond" public_interface="in" private_interface="out" name="time"/>
    <variable units="millivolt" public_interface="in" private_interface="out" name="V"/>
    <variable units="millivolt" public_interface="in" name="V_Ca"/>
    
    <variable units="dimensionless" private_interface="in" name="m"/>
    <variable units="dimensionless" private_interface="in" name="h"/>
    
    <math xmlns="http://www.w3.org/1998/Math/MathML">
      <apply id="i_Ca_T_calculation">
        <eq/>
        <ci> i_Ca_T </ci>
        <apply>
          <times/>
          <ci> g_Ca_T </ci>
          <apply>
            <power/>
            <ci> m </ci>
            <cn cellml:units="dimensionless"> 2.0 </cn>
          </apply>
          <ci> h </ci>
          <apply>
            <minus/>
            <ci> V </ci>
            <ci> V_Ca </ci>
          </apply>
        </apply>
      </apply>
    </math>
  </component>
  
  <component name="T_type_calcium_current_m_gate">
    <variable units="dimensionless" public_interface="out" name="m"/>
    
    <variable units="dimensionless" name="m_infinity"/>
    <variable units="millisecond" name="tau_m"/>
    
    <variable units="millivolt" public_interface="in" name="V"/>
    <variable units="millisecond" public_interface="in" name="time"/>
   
    <math xmlns="http://www.w3.org/1998/Math/MathML">
      <apply id="T_type_calcium_current_m_gate_m_diff_eq">
        <eq/>
        <apply>
          <diff/>
          <bvar>
            <ci> time </ci>
          </bvar>
          <ci> m </ci>
        </apply>
        <apply>
          <divide/>
          <apply>
            <minus/>
            <ci> m_infinity </ci>
            <ci> m </ci>
          </apply>
          <ci> tau_m </ci>
        </apply>
      </apply>
      
      <apply id="T_type_calcium_current_m_gate_m_infinity_calculation">
        <eq/>
        <ci> m_infinity </ci>
        <apply>
          <divide/>
          <cn cellml:units="dimensionless"> 1.0 </cn>
          <apply>
            <plus/>
            <cn cellml:units="dimensionless"> 1.0 </cn>
            <apply>
              <exp/>
              <apply>
                <divide/>
                <apply>
                  <minus/>
                  <apply>
                    <minus/>
                    <ci> V </ci>
                    <cn cellml:units="millivolt"> 56.1 </cn>
                  </apply>
                </apply>
                <cn cellml:units="millivolt"> 10.0 </cn>
              </apply>
            </apply>    
          </apply>
        </apply>
      </apply>
      
      <apply id="T_type_calcium_current_m_gate_tau_m_calculation">
        <eq/>
        <ci> tau_m </ci>
        <apply>
          <plus/>
          <apply>
            <divide/>
            <cn cellml:units="millisecond"> 7.0 </cn>
            <apply>
              <plus/>
              <apply>
                <exp/>
                <apply>
                  <divide/>
                  <apply>
                    <plus/>
                    <ci> V </ci>
                    <cn cellml:units="millivolt"> 50.0 </cn>
                  </apply>
                  <cn cellml:units="millivolt"> 9.0 </cn>
                </apply>
              </apply>
              <apply>
                <exp/>
                <apply>
                  <divide/>
                  <apply>
                    <minus/>
                    <apply>
                      <plus/>
                      <ci> V </ci>
                      <cn cellml:units="millivolt"> 50.0 </cn>
                    </apply>
                  </apply>
                  <cn cellml:units="millivolt"> 9.0 </cn>
                </apply>
              </apply>
            </apply>
          </apply>
          <cn cellml:units="millisecond"> 0.8 </cn>
        </apply>
      </apply>
    </math>
  </component>
  
  <component name="T_type_calcium_current_h_gate">
    <variable units="dimensionless" public_interface="out" name="h"/>
    
    <variable units="dimensionless" name="h_infinity"/>
    <variable units="millisecond" name="tau_h" initial_value="22.0"/>
     
    <variable units="millivolt" public_interface="in" name="V"/>
    <variable units="millisecond" public_interface="in" name="time"/>
   
    <math xmlns="http://www.w3.org/1998/Math/MathML">
      <apply id="T_type_calcium_current_h_gate_diff_eq">
        <eq/>
        <apply>
          <diff/>
          <bvar>
            <ci> time </ci>
          </bvar>
          <ci> h </ci>
        </apply>
        <apply>
          <divide/>
          <apply>
            <minus/>
            <ci> h_infinity </ci>
            <ci> h </ci>
          </apply>
          <ci> tau_h </ci>
        </apply>
      </apply>
      
      <apply id="T_type_calcium_current_h_gate_infinity_calculation">
        <eq/>
        <ci> h_infinity </ci>
        <apply>
          <divide/>
          <cn cellml:units="dimensionless"> 1.0 </cn>
          <apply>
            <plus/>
            <cn cellml:units="dimensionless"> 1.0 </cn>
            <apply>
              <exp/>
              <apply>
                <divide/>
                <apply>
                  <plus/>
                  <ci> V </ci>
                  <cn cellml:units="millivolt"> 86.4 </cn>
                </apply>
                <cn cellml:units="millivolt"> 4.7 </cn>
              </apply>
            </apply>    
          </apply>
        </apply>
      </apply>
    </math>
  </component>
  
  <component name="delayed_rectifier_K_channel_current">
    <variable units="picoA" public_interface="out" name="i_K_dr"/>
    <variable units="millivolt" public_interface="out" name="V_K" initial_value="-80.0"/>
    
    <variable units="nanoS" name="g_K_dr" initial_value="20.0"/>   
   
    <variable units="second" public_interface="in" private_interface="out" name="time"/>
    <variable units="millivolt" public_interface="in" private_interface="out" name="V"/>
     
    <variable units="dimensionless" private_interface="in" name="n"/>
    <variable units="dimensionless" private_interface="in" name="h"/>
    
    <math xmlns="http://www.w3.org/1998/Math/MathML">
      <apply id="i_K_dr_calculation">
        <eq/>
        <ci> i_K_dr </ci>
        <apply>
          <times/>
          <ci> g_K_dr </ci>
          <apply>
            <power/>
            <ci> n </ci>
            <cn cellml:units="dimensionless"> 4.0 </cn>
          </apply>
          <ci> h </ci>
          <apply>
            <minus/>
            <ci> V </ci>
            <ci> V_K </ci>
          </apply>
        </apply>
      </apply>
    </math>
  </component>
  
  <component name="delayed_rectifier_K_channel_current_n_gate">
    <variable units="dimensionless" public_interface="out" name="n"/>
    
    <variable units="dimensionless" name="n_infinity"/>
    <variable units="millisecond" name="tau_n"/>
    
    <variable units="millivolt" public_interface="in" name="V"/>
    <variable units="millisecond" public_interface="in" name="time"/>
   
    <math xmlns="http://www.w3.org/1998/Math/MathML">
      <apply id="delayed_rectifier_K_channel_current_n_gate_n_diff_eq">
        <eq/>
        <apply>
          <diff/>
          <bvar>
            <ci> time </ci>
          </bvar>
          <ci> n </ci>
        </apply>
        <apply>
          <divide/>
          <apply>
            <minus/>
            <ci> n_infinity </ci>
            <ci> n </ci>
          </apply>
          <ci> tau_n </ci>
        </apply>
      </apply>
      
      <apply id="delayed_rectifier_K_channel_current_n_gate_n_infinity_calculation">
        <eq/>
        <ci> n_infinity </ci>
        <apply>
          <divide/>
          <cn cellml:units="dimensionless"> 1.0 </cn>
          <apply>
            <plus/>
            <cn cellml:units="dimensionless"> 1.0 </cn>
            <apply>
              <exp/>
              <apply>
                <divide/>
                <apply>
                  <minus/>
                  <apply>
                    <plus/>
                    <ci> V </ci>
                    <cn cellml:units="millivolt"> 25.0 </cn>
                  </apply>
                </apply>
                <cn cellml:units="millivolt"> 15.0 </cn>
              </apply>
            </apply>    
          </apply>
        </apply>
      </apply>
      
      <apply id="delayed_rectifier_K_channel_current_n_gate_tau_n_calculation">
        <eq/>
        <ci> tau_n </ci>
        <apply>
          <plus/>
          <apply>
            <divide/>
            <cn cellml:units="millisecond"> 15.0 </cn>
            <apply>
              <plus/>
              <apply>
                <exp/>
                <apply>
                  <divide/>
                  <apply>
                    <plus/>
                    <ci> V </ci>
                    <cn cellml:units="millivolt"> 30.0 </cn>
                  </apply>
                  <cn cellml:units="millivolt"> 15.0 </cn>
                </apply>
              </apply>
              <apply>
                <exp/>
                <apply>
                  <divide/>
                  <apply>
                    <minus/>
                    <apply>
                      <plus/>
                      <ci> V </ci>
                      <cn cellml:units="millivolt"> 30.0 </cn>
                    </apply>
                  </apply>
                  <cn cellml:units="millivolt"> 15.0 </cn>
                </apply>
              </apply>
            </apply>
          </apply>
          <cn cellml:units="millisecond"> 1.0 </cn>
        </apply>
      </apply>
    </math>
  </component>
  
  <component name="delayed_rectifier_K_channel_current_h_gate">
    <variable units="dimensionless" public_interface="out" name="h"/>
    
    <variable units="dimensionless" name="h_infinity"/>
    <variable units="millisecond" name="tau_h" initial_value="1000.0"/>
     
    <variable units="millivolt" public_interface="in" name="V"/>
    <variable units="millisecond" public_interface="in" name="time"/>
   
    <math xmlns="http://www.w3.org/1998/Math/MathML">
      <apply id="delayed_rectifier_K_channel_current_h_gate_diff_eq">
        <eq/>
        <apply>
          <diff/>
          <bvar>
            <ci> time </ci>
          </bvar>
          <ci> h </ci>
        </apply>
        <apply>
          <divide/>
          <apply>
            <minus/>
            <ci> h_infinity </ci>
            <ci> h </ci>
          </apply>
          <ci> tau_h </ci>
        </apply>
      </apply>
      
      <apply id="delayed_rectifier_K_channel_current_h_gate_infinity_calculation">
        <eq/>
        <ci> h_infinity </ci>
        <apply>
          <plus/>
          <apply>
            <divide/>
            <cn cellml:units="dimensionless"> 0.7 </cn>
            <apply>
              <plus/>
              <cn cellml:units="dimensionless"> 1.0 </cn>
              <apply>
                <exp/>
                <apply>
                  <divide/>
                  <apply>
                    <minus/>
                    <apply>
                      <plus/>
                      <ci> V </ci>
                      <cn cellml:units="millivolt"> 35.0 </cn>
                    </apply>
                  </apply>
                  <cn cellml:units="millivolt"> 10.0 </cn>
                </apply>
              </apply>
            </apply>    
          </apply>
          <cn cellml:units="dimensionless"> 0.3 </cn>
        </apply>
      </apply>
    </math>
  </component>  
  
  <component name="M_like_K_current">
    <variable units="picoA" public_interface="out" name="i_M"/>
    
    <variable units="nanoS" name="g_M" initial_value="4.0"/>   
    
    <variable units="millisecond" public_interface="in" private_interface="out" name="time"/>
    <variable units="millivolt" public_interface="in" private_interface="out" name="V"/>
    <variable units="millivolt" public_interface="in" name="V_K"/>
    
    <variable units="dimensionless" private_interface="in" name="n"/>
    
    <math xmlns="http://www.w3.org/1998/Math/MathML">
      <apply id="i_M_calculation">
        <eq/>
        <ci> i_M </ci>
        <apply>
          <times/>
          <ci> g_M </ci>
          <ci> n </ci>
          <apply>
            <minus/>
            <ci> V </ci>
            <ci> V_K </ci>
          </apply>
        </apply>
      </apply>
    </math>
  </component>
  
  <component name="M_like_K_current_n_gate">
    <variable units="dimensionless" public_interface="out" name="n"/>
    
    <variable units="dimensionless" name="n_infinity"/>
    <variable units="millisecond" name="tau_n"/>
    
    <variable units="millivolt" public_interface="in" name="V"/>
    <variable units="millisecond" public_interface="in" name="time"/>
   
    <math xmlns="http://www.w3.org/1998/Math/MathML">
      <apply id="M_like_K_current_n_gate_n_diff_eq">
        <eq/>
        <apply>
          <diff/>
          <bvar>
            <ci> time </ci>
          </bvar>
          <ci> n </ci>
        </apply>
        <apply>
          <divide/>
          <apply>
            <minus/>
            <ci> n_infinity </ci>
            <ci> n </ci>
          </apply>
          <ci> tau_n </ci>
        </apply>
      </apply>
      
      <apply id="M_like_K_current_n_gate_n_infinity_calculation">
        <eq/>
        <ci> n_infinity </ci>
        <apply>
          <divide/>
          <cn cellml:units="dimensionless"> 1.0 </cn>
          <apply>
            <plus/>
            <cn cellml:units="dimensionless"> 1.0 </cn>
            <apply>
              <exp/>
              <apply>
                <divide/>
                <apply>
                  <minus/>
                  <apply>
                    <plus/>
                    <ci> V </ci>
                    <cn cellml:units="millivolt"> 37.0 </cn>
                  </apply>
                </apply>
                <cn cellml:units="millivolt"> 4.0 </cn>
              </apply>
            </apply>    
          </apply>
        </apply>
      </apply>
      
      <apply id="M_like_K_current_n_gate_tau_n_calculation">
        <eq/>
        <ci> tau_n </ci>
        <apply>
          <divide/>
          <cn cellml:units="millisecond"> 80.0 </cn>
          <apply>
            <plus/>
            <apply>
              <exp/>
              <apply>
                <divide/>
                <apply>
                  <plus/>
                  <ci> V </ci>
                  <cn cellml:units="millivolt"> 30.0 </cn>
                </apply>
                <cn cellml:units="millivolt"> 15.0 </cn>
              </apply>
            </apply>
            <apply>
              <exp/>
              <apply>
                <divide/>
                <apply>
                  <minus/>
                  <apply>
                    <plus/>
                    <ci> V </ci>
                    <cn cellml:units="millivolt"> 30.0 </cn>
                  </apply>
                </apply>
                <cn cellml:units="millivolt"> 15.0 </cn>
              </apply>
            </apply>
          </apply>
        </apply>
      </apply>
    </math>
  </component>
  
  <component name="inward_rectifier_K_current">
    <variable units="picoA" public_interface="out" name="i_ir"/>
    
    <variable units="nanoS" name="g_ir" initial_value="1.71"/>   
    
    <variable units="millisecond" public_interface="in" private_interface="out" name="time"/>
    <variable units="millivolt" public_interface="in" private_interface="out" name="V"/>
    <variable units="millivolt" public_interface="in" name="V_K"/>
    
    <variable units="dimensionless" private_interface="in" name="n_infinity"/>
    
    <math xmlns="http://www.w3.org/1998/irath/irathirL">
      <apply id="i_ir_calculation">
        <eq/>
        <ci> i_ir </ci>
        <apply>
          <times/>
          <ci> g_ir </ci>
          <ci> n_infinity </ci>
          <apply>
            <minus/>
            <ci> V </ci>
            <ci> V_K </ci>
          </apply>
        </apply>
      </apply>
    </math>
  </component>
  
  <component name="inward_rectifier_K_current_n_gate">
    <variable units="dimensionless" public_interface="out" name="n_infinity"/>   
    <variable units="millivolt" public_interface="in" name="V"/>
    
    <math xmlns="http://www.w3.org/1998/Math/MathML">
      <apply id="inward_rectifier_K_current_n_gate_n_infinity_calculation">
        <eq/>
        <ci> n_infinity </ci>
        <apply>
          <plus/>
          <apply>
            <times/>
            <cn cellml:units="dimensionless"> 0.8 </cn>
            <apply>
              <divide/>
              <cn cellml:units="dimensionless"> 1.0 </cn>
              <apply>
                <plus/>
                <cn cellml:units="dimensionless"> 1.0 </cn>
                <apply>
                  <exp/>
                  <apply>
                    <divide/>
                    <apply>
                      <plus/>
                      <ci> V </ci>
                      <cn cellml:units="millivolt"> 80.0 </cn>
                    </apply>
                    <cn cellml:units="millivolt"> 12.0 </cn>
                  </apply>
                </apply>    
              </apply>
            </apply>
          </apply>
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    <rdf:li>Neuron</rdf:li>
    <rdf:li>calcium dynamics</rdf:li>
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    <vCard:Given>Lazar</vCard:Given>
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    <vCard:Orgname>The University of Auckland</vCard:Orgname>
    <vCard:Orgunit>The Bioengineering Institute</vCard:Orgunit>
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    <dcterms:modified rdf:resource="rdf:#989c45b5-ded3-4574-9203-91e7b128b08e"/>
    <rdf:value>The new version of this model has been re-coded to remove the reaction element and replace it with a simple MathML description of the model reaction kinetics. This is thought to be truer to the original publication, and information regarding the enzyme kinetics etc will later be added to the metadata through use of an ontology. &#13;
&#13;
The model does not run in the PCEnv simulator because the model is underconstrained.  Apparently i_ir could not be defined - but there is an equation included to define i_ir, and all the elements in this equation either have an initial value or a defining equation themselves.  So I'm not sure what exactly is missing.</rdf:value>
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    <vCard:Given>Kevin</vCard:Given>
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    <vCard:Other>J</vCard:Other>
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    <vCard:Given>Arthur</vCard:Given>
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    <vCard:FN>Catherine Lloyd</vCard:FN>
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    <vCard:Given>Stanko</vCard:Given>
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    <dcterms:W3CDTF>2000-09</dcterms:W3CDTF>
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    <vCard:Given>Catherine</vCard:Given>
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  <rdf:Description rdf:about="rdf:#cd243f4b-d2a5-4154-92dd-d37e472d2604">
    <rdf:type rdf:resource="http://www.cellml.org/bqs/1.0#Person"/>
    <vCard:N rdf:resource="rdf:#e73b2d9a-733d-4573-9d55-147fb53f6b95"/>
  </rdf:Description>
  <rdf:Description rdf:about="rdf:#c62a0bff-fe9e-4b42-8166-4f9680264465">
    <rdf:type rdf:resource="http://www.cellml.org/bqs/1.0#Person"/>
    <vCard:N rdf:resource="rdf:#cfa15fc4-a7ea-44a5-9393-fd3df1c98feb"/>
  </rdf:Description>
  <rdf:Description rdf:about="rdf:#b435c23e-a9cd-44f7-a1e3-29067ad8c599">
    <vCard:Given>Andrew</vCard:Given>
    <vCard:Family>LeBeau</vCard:Family>
    <vCard:Other>P</vCard:Other>
  </rdf:Description>
  <rdf:Description rdf:about="rdf:#a419a90c-bc34-4e50-b05c-03c75ed33dfb">
    <dc:creator rdf:resource="rdf:#d336198e-a46d-4e31-882a-ce15148a190c"/>
  </rdf:Description>
  <rdf:Description rdf:about="rdf:#e68f29ca-5d8b-4429-92af-b2e11b818b79">
    <rdf:type rdf:resource="http://www.cellml.org/bqs/1.0#Person"/>
    <vCard:N rdf:resource="rdf:#59dc4ac4-3013-41ad-b66f-ad02ac8499e8"/>
  </rdf:Description>
</rdf:RDF>
</model>