Sodium-calcium exchange tail current in atrial myocytes of the rabbit — An index of subsarcolemmal calcium concentrations?

In cardiac cells, sodium-calcium exchange is important in regulation of intracellular calcium concentration as a primary mechanism of calcium extrusion. In the present study, the effect of calcium buffers, EGTA, BAPTA and Indo-1 on the process that activates the inward Na-Ca exchange current was investigated by analyzing the voltage dependence and the time course of the tail currents, and the change of the inward tail current in hypoxic condition and in various cardiomyopathic conditions (adriamycin and hyperthyroidism). Whole cell patch clamp technique with intracellular perfusion was used in rabbit atrial myocytes.