Andreyev A Y, Fahy B, Fiskum G
Department of Anesthesiology, University of Maryland, School of Medicine, Baltimore 21201, USA.
FEBS Lett. 1998 Nov 20;439(3):373-6. doi: 10.1016/s0014-5793(98)01394-5.
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.
脑线粒体对钙离子的摄取会以一种对环孢菌素A不敏感的方式诱导释放高达40%的总细胞色素c。在ATP和镁离子存在的情况下，这一过程并不伴随着线粒体肿胀。在这些条件下膜电位会有适度下降，但通过添加EGTA + A23187去除积累的钙离子后它会完全恢复，而仅添加EGTA则不能。这些观察结果提供了证据，表明脑线粒体释放细胞色素c并不需要膜通透性转换。然而，脑线粒体在没有ATP和镁离子的情况下会发生通透性转换，这会导致对环孢菌素A敏感的大幅度肿胀、钙离子摄取能力丧失以及基质溶质的释放。
