Inhibition of the Na+/Ca2+ exchange in cardiac sarcolemmal vesicles by amiloride.
The pyrazine diuretic amiloride inhibits the Na+/Ca2+ exchange activity of cardiac sarcolemmal vesicles in a concentration-dependent way. A good relationship between the uptake of amiloride by the vesicles and the inhibition of the exchanger has been found. Kinetic analyses indicate that the inhibition of Na+/Ca2+ exchange activity by amiloride is non-competitively removed by Ca2+ and competitively overcome by an outwardly directed Na+ gradient.
D000584:Amiloride / Q000378:metabolism / Q000494:pharmacology*; D000818:Animals; D001667:Binding, Competitive; D002118:Calcium / Q000378:metabolism; D002352:Carrier Proteins / Q000037:antagonists & inhibitors*; D002417:Cattle; D007700:Kinetics; D009206:Myocardium / Q000378:metabolism*; D012508:Sarcolemma / Q000378:metabolism*; D012964:Sodium / Q000378:metabolism; D019831:Sodium-Calcium Exchanger
D002352:Carrier Proteins; D019831:Sodium-Calcium Exchanger; D000584:Amiloride; D012964:Sodium; D002118:Calcium