Physiological role of transverse-axial tubular system in cardiac ventricular myocytes: a simulation study

Experimental data related to the transverse-axial tubular system of guinea pig and rat ventricular myocytes were incorporated into quantitative models of their electrical activity. The results of simulations suggest that activity-dependent depletion of Ca 2+ within the tubular lumen decreases the intracellular Ca 2+ load and intracellular Ca 2+ transients in both species. However, considerable species differences in the magnitude of the depletion, its frequency dependence and the resulting effect on cellular activity were observed