- Author:
- Shelley Fong <sfon036@UoA.auckland.ac.nz>
- Date:
- 2022-05-20 10:22:46+12:00
- Desc:
- Adding exposure files
- Permanent Source URI:
- https://models.physiomeproject.org/workspace/818/rawfile/a67177c16af102ea8ec4d69929c771407a9803c7/exposure/exposure_frontpage.rst
About this model
====================
This is a bond graph model on the contraction of vascular smooth muscle cell. It is based on the work of `Hai and Murphy (1988) <https://models.physiomeproject.org/exposure/75b1dd114e0eecf1e73f62d295f2a64f>`_.
**INPUTS:**
- Cyclic guanosine monophosphate
**OUTPUTS:**
- Stress generated by crossbridge contraction
**REACTIONS:**
- Re12m: Phosphorylation of myosin light chain (M) to M\ :sub:`p`\
- Re34m: Binding of actin (A) to M\ :sub:`p`\ to form cross bridge (AM\ :sub:`p`\)
- Re56m: Cross bridge formation by phosphorylation of a latch bridge (AM)
- Re78m: Detachment of latch bridge into A and M
Model status
=============
The current CellML implementation runs in OpenCOR.
Model overview
===================
This model is based on existing kinetic model by `Hai and Murphy (1988) <https://models.physiomeproject.org/exposure/75b1dd114e0eecf1e73f62d295f2a64f>`_, where the mathematics are translated into the bond-graph formalism. This describes the model in energetic terms and forces adherence to the laws of thermodynamics.
In this workspace, two forms of the contraction model are presented: the original Hai-Murphy model, and the model altered by `Yang et. al. (2005) <https://doi.org/10.1152/ajpheart.00216.2004>`_. The latter is used towards coupling with `guanylyl cyclase metabolism <https://models.physiomeproject.org/e/87d>`_.
.. figure:: exposure/SM_contraction.png
:width: 100%
:align: center
:alt: SM_contraction
Fig. 1. Smooth muscle contraction module
For the above bond-graph, a '0' node refers to a junction where all chemical potentials are the same. A '1' node refers to all fluxes being the same going in and out of the junction.
.. csv-table:: List of chemical species
:header: "Abbreviation", "Name"
:widths: 5, 15
"cGMP", "Cyclic guanosine monophosphate"
"M", "Myosin light chain"
"M\ :sub:`p`", "Myosin light chain, phosphorylated"
"A", "Actin"
"AM", "Latch bridge"
"AM\ :sub:`p`", "Cross bridge"
"Ca", "Calcium ion"
Parameter finding
~~~~~~~~~~~~~~~~~
A description of the process to find bond-graph parameters is shown in the folder `parameter_finder <parameter_finder>`_, which relies on the:
1. stoichiometry of system
2. kinetic constants for forward/reverse reactions
- If not already, all reactions are made reversible by assigning a small value to the reverse direction.
3. `linear algebra script <https://models.physiomeproject.org/workspace/818/file/bb5de0201cebfb862c2cfd4d37bdbdc8986d14ed/parameter_finder/find_BG_parameters.py>`_.
Here, this solve process is performed in Python.
Original kinetic model
======================
`Hai and Murphy (1988) <https://models.physiomeproject.org/exposure/75b1dd114e0eecf1e73f62d295f2a64f>`_.
