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Reactive oxygen species induce swelling and cytochrome c release but not transmembrane depolarization in isolated rat brain mitochondria
Author(s) -
Galindo María F,
Jordán Joaquín,
GonzálezGarcía Carmen,
Ceña Valentín
Publication year - 2003
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1038/sj.bjp.0705309
Subject(s) - mitochondrion , ruthenium red , cytochrome c , superoxide , reactive oxygen species , depolarization , biochemistry , calcium , chemistry , membrane potential , mitochondrial ros , mitochondrial apoptosis induced channel , mitochondrial permeability transition pore , nadh dehydrogenase , nad+ kinase , biology , microbiology and biotechnology , apoptosis , biophysics , enzyme , programmed cell death , mitochondrial dna , organic chemistry , gene
In this study, we have used isolated brain mitochondria to investigate the effects of superoxide anions (O 2 − ) on mitochondrial parameters related to apoptosis, such as swelling, potential, enzymatic activity, NAD(P)H, cytochrome c release, and caspase activity. Addition of the reactive oxygen species (ROS) generator KO 2 produced brain mitochondrial swelling, which was blocked by cyclosporin A (CSA), and which was Ca 2+ independent. Calcium induced mitochondrial swelling only at high concentrations and in the presence of succinate. This correlated with the increase in O 2 − production detected with hydroethidine in mitochondrial preparations exposed to Ca 2+ and the fact that ROS were required for Ca 2+ ‐induced mitochondrial swelling. Superoxide anions, but not Ca 2+ , decreased citrate synthase and dehydrogenase enzymatic activities and dropped total mitochondrial NAD(P)H levels. Calcium, but not O 2 − , triggered a rapid loss of mitochondrial potential. Calcium‐induced Δψ m dissipation was inhibited by Ruthenium Red, but not by CSA. Calcium‐ and superoxide‐induced mitochondrial swelling released cytochrome c and increased caspase activity from isolated mitochondria in a CS A‐sensitive manner. In summary, superoxide potently triggers mitochondrial swelling and the release of proteins involved in activation of postmitochondrial apoptotic pathways in the absence of mitochondrial depolarization.British Journal of Pharmacology (2003) 139 , 797–804. doi: 10.1038/sj.bjp.0705309