Inhibition of Na+-dependent Ca2+ efflux from heart mitochondria by amiloride analogues.
The Na+-induced release of accumulated Ca2+ from heart mitochondria is inhibited by amiloride, benzamil and several other amiloride analogues. These drugs do not affect uptake or release of Ca2+ mediated by the ruthenium red-sensitive uniporter and their effects, like those of diltiazem and other Ca2+-antagonists, appear to be localized principally at the Na+/Ca2+ antiporter of the mitochondrion. Benzamil inhibits Na+/Ca2+ antiport non-competitively with respect to [Na+] with a Ki of 167 microM. In the presence of 1.5 mM Pi the Ki for benzamil inhibition of this reaction is decreased to 87 microM.
D000584:Amiloride / Q000031:analogs & derivatives / Q000494:pharmacology*; D000818:Animals; D001693:Biological Transport, Active / Q000187:drug effects; D002118:Calcium / Q000378:metabolism*; D002417:Cattle; D066298:In Vitro Techniques; D008929:Mitochondria, Heart / Q000378:metabolism*; D011719:Pyrazines / Q000494:pharmacology*; D012964:Sodium / Q000502:physiology*
D011719:Pyrazines; C013407:benzamil; D000584:Amiloride; D012964:Sodium; D002118:Calcium