Mathematical modeling of the sinoatrial node cell in the rabbit heart

[摘要] A mathematical model has been developed for the rabbit sinoatrial node (SAN) cardiac pacemaker cell, that is based on experimental results from whole-cell voltage clamp and action potential studies on single enzymatically-isolated pacemaker cells. The model consists of two parts, a model of sarcolemma, and a fluid compartment model of the intra and extracellular media. The sarcolemmal membrane model is of Hodgkin-Huxley form, and includes mathematical descriptions of the major ion channels present in mammalian cardiac pacemaker cells, as well as, descriptions of the Na$sp+$/K$sp+$ and Ca$sp{2+}$ pump and the Na$sp+$/Ca$sp{2+}$ exchanger currents. The fluid compartment model is based on a material balance for the ion concentrations in the intracellular medium (Na$sp+$, K$sp+$ and Ca$sp{2+}$); concentrations of these ions are considered constant in the extracellular medium. Provision is made in this model for Ca$sp{2+}$ buffering in the intracellular medium, as well as the uptake and release of Ca$sp{2+}$ by the sarcoplasmic reticulum (SR). Our model is able to provide good fits to both voltage clamp and action potential data from several published sources, and has provided insights into the biophysical interactions and the functional roles of several currents underlying the pacemaker potential of the rabbit SAN cell.

[发布机构] Rice University

[效力级别] Physiology