Iontově koncentrační změny v tubulárním systému srdečních komorových buněk potkana

We present a design of a model of rat ventricular cardiomyocyte with transverse-axial tubular system and the results of the first simulations of tubular ionic concentration changes at different stimulation rates. The morphology of tubular system and the distribution of ionic channels in tubular membrane were described to meet the recent data. Exploration of activity-dependent changes in tubular ionic concentrations revealed an increase in relative Ca2+ depletion from 7.3 % to 14 % when increasing the stimulation frequency from 1 Hz to 5 Hz. Meanwhile, relative K+ accumulation decreased from 4.3 % to 3 %. These effects led to a limitation of intracellular Ca2+ overload