Interaction of Sr2+ with Ca2+-induced Ca2+ release in mitochondria.
Respiring rat liver mitochondria are known to spontaneously release the Ca2+ taken up when they have accumulated Ca2+ over a certain threshold, while Sr2+ and Mn2+ are well tolerated and retained. We have studied the interaction of Sr2+ with Ca2+ release. When Sr2+ was added to respiring mitochondria simultaneously with or soon after the addition of Ca2+, the release was potently inhibited or reversed. On the other hand, when Sr2+ was added before Ca2+, the release was stimulated. Ca2+-induced mitochondrial damage and release of accumulated Ca2+ is generally believed to be due to activation of mitochondrial phospholipase A (EC 3.1.1.4.) by Ca2+. However, isolated mitochondrial phospholipase A activity was little if at all inhibited by Sr2+. The Ca2+-release may thus be triggered by some Ca2+-dependent function other than phospholipase.
Saris
N E
NE
Department of Medical Chemistry, University of Helsinki, Finland.
van den Bosch
H
H
D000818:Animals; D002118:Calcium / Q000378:metabolism* / Q000494:pharmacology; D007700:Kinetics; D008930:Mitochondria, Liver / Q000187:drug effects / Q000378:metabolism*; D010741:Phospholipases A / Q000378:metabolism; D051381:Rats; D013324:Strontium / Q000494:pharmacology*
D010741:Phospholipases A; D002118:Calcium; D013324:Strontium