Temperature dependence of the atractyloside-induced mitochondrial Ca2+ release.
1. Mitochondrial Ca2+, accumulated by succinate oxidation was released by addition of 50 microM atractyloside. Beside this Ca2+ efflux, a large oxidation of pyridine nucleotides and sustained membrane depolarization occurs. An absolute requirement for acetate to support Ca2+ release is demonstrated. 2. Membrane de-energization, NAD(P)H oxidation, and Ca2+ efflux as induced by atractyloside were temperature-dependent, since it occurs when mitochondria are incubated at 22 degrees C and was abolished at 4 degrees C. 3. Taking into account this latter, the effects of atractyloside on mitochondrial Ca2+ release appears not to be a simple result of the binding of the inhibitor to adenine nucleotide translocase. 4. It is proposed that the mechanism involved in atractyloside-driven membrane permeability to Ca2+ must be related with the transference of the conformational change of the carrier, to another membrane structure responsible for the maintenance permeability to ions.
Chávez
E
E
Departamento de Bioquímica, Instituto Nacional de Cardiología, Ignacio Chávez, México, D.F.
Osornio
A
A
D000818:Animals; D001278:Atractyloside / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism*; D006027:Glycosides / Q000494:pharmacology*; D066298:In Vitro Techniques; D008560:Membrane Fluidity / Q000187:drug effects; D008564:Membrane Potentials / Q000187:drug effects; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism*; D000226:Mitochondrial ADP, ATP Translocases / Q000378:metabolism; D008933:Mitochondrial Swelling / Q000187:drug effects; D051381:Rats; D013696:Temperature
D006027:Glycosides; D001278:Atractyloside; D000226:Mitochondrial ADP, ATP Translocases; D002118:Calcium