[Factors affect Na(+)-Ca2+ exchange in rat's cardiomyocytes and protein-reconstituted liposomes]

Rat's Ca-resistant ventricular myocytes and reconstituted liposomes of canine cardiac sarcolemma were used in analysing factors affecting Na(+)-Ca2+ exchange system. Decrease in extracellular (extravesicular) Na+ or increase in intracellular Na+ by inhibition of the Za(+)-K(+)-ATPase with ouabain stimulated the Na(+)-Ca2+ exchange. Mn2+, an antagonist of Na(+)-Ca2+ exchange, dose-dependently inhibited the Na(+)-dependent Ca2+ uptake. However, verapamil had no effect on it. Arachidonic acid and lipid peroxides caused by incubation with-H2O2 significantly stimulated Na(+)-Ca2+ exchange in a dose-dependent fashion.