Calcium-induced Cytochrome c release from CNS mitochondria is associated with the permeability transition and rupture of the outer membrane
Article first published online: 27 FEB 2002
Journal of Neurochemistry
Volume 80, Issue 2, pages 207–218, January 2002
How to Cite
Brustovetsky, N., Brustovetsky, T., Jemmerson, R. and Dubinsky, J. M. (2002), Calcium-induced Cytochrome c release from CNS mitochondria is associated with the permeability transition and rupture of the outer membrane. Journal of Neurochemistry, 80: 207–218. doi: 10.1046/j.0022-3042.2001.00671.x
- Issue published online: 27 FEB 2002
- Article first published online: 27 FEB 2002
- Received July 10, 2001; revised manuscript received September 27, 2001; accepted September 28, 2001.
The mechanisms of Ca2+-induced release of Cytochrome c (Cyt c) from rat brain mitochondria were examined quantitatively using a capture ELISA. In 75 or 125 mm KCl-based media 1.4 µmol Ca2+/mg protein caused depolarization and mitochondrial swelling. However, this resulted in partial Cyt c release only in 75 mm KCl. The release was inhibited by Ru360, an inhibitor of the Ca2+ uniporter, and by cyclosporin A plus ADP, a combination of mitochondrial permeability transition inhibitors. Transmission electron microscopy (TEM) revealed that Ca2+-induced swelling caused rupture of the outer membrane only in 75 mm KCl. Koenig's polyanion, an inhibitor of mitochondrial porin (VDAC), enhanced swelling and amplified Cyt c release. Dextran T70 that is known to enhance mitochondrial contact site formation did not prevent Cyt c release. Exposure of cultured cortical neurons to 500 µm glutamate for 5 min caused Cyt c release into the cytosol 30 min after glutamate removal. MK-801 or CsA inhibited this release. Thus, the release of Cyt c from CNS mitochondria induced by Ca2+in vitro as well as in situ involved the mPT and appeared to require the rupture of the outer membrane.