Cardiac sodium channel Markov model with temperature dependence and recovery from inactivation

Model Status

This CellML model is known to run in both PCEnv and COR to recreate the published results. The units have been checked and they are consistent. In this particular version of the model the membrane potential is held at -120mV. Thanks to Joseph Greenstein, Stefan Mann, Alan Garny and Martin Fink for their help in curating this model. There is also a PCEnv session associated with this model.

Model Structure

ABSTRACT: A Markov model of the cardiac sodium channel is presented. The model is similar to the CA1 hippocampal neuron sodium channel model developed by Kuo and Bean (1994. Neuron. 12:819 - 829) with the following modifications: 1) an additional open state is added; 2) open-inactivated transitions are made voltage-dependent; and 3) channel rate constants are exponential functions of enthalpy, entropy, and voltage and have explicit temperature dependence. Model parameters are determined using a simulated annealing algorithm to minimize the error between model responses and various experimental data sets. The model reproduces a wide range of experimental data including ionic currents, gating currents, tail currents, steady-state inactivation, recovery from inactivation, and open time distributions over a temperature range of 10C to 25C. The model also predicts measures of single channel activity such as first latency, probability of a null sweep, and probability of reopening.

The complete original paper reference is cited below:

Cardiac Sodium Channel Markov Model with Temperature Dependence and Recovery from Inactivation, Lisa A. Irvine, M. Saleet Jafri, and Raimond L. Winslow, 1999, Biophysical Journal , 76, 1868 - 1885. ( Full text and PDF versions of this article are available to subscribers on the Biophysical Journal website). PubMed ID: 10096885

State diagram for the cardiac sodium channel Markov model. C0-C4 are closed states, O1 and O2 are open states, C0I-C4I are closed-inactivated states, and I is the inactivated state. All rate constants are voltage- and temperature-dependent except for those governing transitions between closed and closed-inactivated states, which are only temperature-dependent.