Cardiac sodium channel Markov model with temperature dependence and recovery from inactivation.
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 10 degrees C to 25 degrees C. The model also predicts measures of single channel activity such as first latency, probability of a null sweep, and probability of reopening.
Irvine
L A
LA
Department of Biomedical Engineering, Center for Computational Medicine and Biology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.
Jafri
M S
MS
Winslow
R L
RL
D000465:Algorithms; D000818:Animals; D055592:Biophysical Phenomena; D001703:Biophysics; D015640:Ion Channel Gating; D007700:Kinetics; D008390:Markov Chains; D008564:Membrane Potentials; D008955:Models, Cardiovascular; D009206:Myocardium / Q000378:metabolism*; D026941:Sodium Channel Blockers; D015222:Sodium Channels / Q000378:metabolism*; D013696:Temperature; D013816:Thermodynamics
D026941:Sodium Channel Blockers; D015222:Sodium Channels