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Calcium‐induced Cytochrome c release from CNS mitochondria is associated with the permeability transition and rupture of the outer membrane
Author(s) -
Brustovetsky Nickolay,
Brustovetsky Tatiana,
Jemmerson Ronald,
Dubinsky Janet M.
Publication year - 2002
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1046/j.0022-3042.2001.00671.x
Subject(s) - mitochondrial permeability transition pore , cytochrome c , mitochondrion , uniporter , biophysics , cytosol , depolarization , voltage dependent anion channel , glutamate receptor , swelling , membrane potential , inner mitochondrial membrane , calcium , chemistry , biochemistry , biology , bacterial outer membrane , apoptosis , programmed cell death , materials science , receptor , organic chemistry , escherichia coli , gene , composite material , enzyme
The mechanisms of Ca 2+ ‐induced release of Cytochrome c (Cyt c ) from rat brain mitochondria were examined quantitatively using a capture ELISA. In 75 or 125 m m KCl‐based media 1.4 µmol Ca 2+ /mg protein caused depolarization and mitochondrial swelling. However, this resulted in partial Cyt c release only in 75 m m KCl. The release was inhibited by Ru 360 , an inhibitor of the Ca 2+ uniporter, and by cyclosporin A plus ADP, a combination of mitochondrial permeability transition inhibitors. Transmission electron microscopy (TEM) revealed that Ca 2+ ‐induced swelling caused rupture of the outer membrane only in 75 m m 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 µ m 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 Ca 2+ in vitro as well as in situ involved the mPT and appeared to require the rupture of the outer membrane.