Cytochrome c release from brain mitochondria is independent of the mitochondrial permeability transition.
Ca2+ uptake by brain mitochondria induces the release of up to 40% of total cytochrome c in a cyclosporin A-insensitive manner. In the presence of ATP and Mg2+, this process is not accompanied by mitochondrial swelling. There is a moderate decrease in membrane potential under these conditions, but it is completely reversible upon removal of accumulated Ca2+ by addition of EGTA+A23187 but not by EGTA alone. These observations provide evidence that cytochrome c release from brain mitochondria does not require the membrane permeability transition. However, brain mitochondria can undergo the permeability transition in the absence of ATP and Mg2+, which results in cyclosporin A-sensitive large amplitude swelling, loss of Ca2+ uptake capacity and release of matrix solutes.
Andreyev
A Y
AY
Department of Anesthesiology, University of Maryland, School of Medicine, Baltimore 21201, USA.
Fahy
B
B
Fiskum
G
G
D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D001921:Brain / Q000166:cytology / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism; D002463:Cell Membrane Permeability; D003574:Cytochrome c Group / Q000378:metabolism*; D066298:In Vitro Techniques; D008274:Magnesium / Q000378:metabolism; D008928:Mitochondria / Q000378:metabolism*; D051381:Rats
D003574:Cytochrome c Group; D000255:Adenosine Triphosphate; D008274:Magnesium; D002118:Calcium