title: Sensitivity of Ca2+ transport of mitochondria to reactive oxygen species.
abstract: The relationship between Ca2+ transport and energy transduction of myocardial mitochondria in the presence of reactive oxygen species was investigated. Following treatment with oxygen free radicals [superoxide(O2.-) or hydroxyl radical (.OH)], lipid free radicals in myocardial mitochondrial membrane could be detected by using the method of EPR spin trap. Simultaneously there were obvious alterations in the free Ca2+ ([Ca2+]m) in the mitochondrial matrix; the physical state of membrane lipid; the efficiency of oxidative phosphorylation (ADP/O); the value of the respiratory control ratio (RCR); and the membrane potential of the inner membrane of myocardial mitochondria. If the concentrations of reactive oxygen species were reduced by about 30%, the alterations in the physical state of the membrane lipid and energy transduction of myocardial mitochondria were not observed, but the changes in Ca2+ homeostasis remained. We conclude that Ca2+ transport by myocardial mitochondria is more sensitive to agents such as O2.- or OH, etc. than are oxidation phosphorylation and the respiratory chain.
authors.affiliation: National Laboratory of Biomacromolecules, Institute of Biophysics, Academia Sinica, China.
authors.forename: Z W
authors.initials: ZW
authors.lastname: Yang
authors.forename: F Y
authors.initials: FY
authors.lastname: Yang
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism*; D003497:Cyclic N-Oxides; D004161:Diphenylhexatriene; D004578:Electron Spin Resonance Spectroscopy; D005454:Fluorescence Polarization; D017665:Hydroxyl Radical / Q000494:pharmacology*; D017136:Ion Transport / Q000187:drug effects; D007655:Ketoglutarate Dehydrogenase Complex / Q000378:metabolism; D008297:Male; D008564:Membrane Potentials; D008929:Mitochondria, Heart / Q000187:drug effects / Q000378:metabolism*; D010085:Oxidative Phosphorylation / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D017382:Reactive Oxygen Species / Q000502:physiology*; D013481:Superoxides / Q000494:pharmacology*
chemical_list: D003497:Cyclic N-Oxides; D017382:Reactive Oxygen Species; D013481:Superoxides; D004161:Diphenylhexatriene; D017665:Hydroxyl Radical; C017245:5,5-dimethyl-1-pyrroline-1-oxide; D007655:Ketoglutarate Dehydrogenase Complex; D002118:Calcium