Cyclosporin A-sensitive cytochrome c release and activation of external pathway of NADH oxidation in liver mitochondria due to pore opening by acidification of phosphate-containing incubation medium.
Acidification of a high phosphate incubation medium from pH 7.4 to 6.5 promotes increase in rates of succinate oxidation and exogenous NADH oxidation via external (rotenone-and myxothiazol-resistant) pathway by factors 2 and 2.3 respectively. Cyclosporin A prevents these effects. To measure the cytochrome c release, mitochondrial cytochrome c concentration was calculated from absorption spectrum of alpha-band of cytochromes c + c1. The cytochrome c release is shown to be equal to 27 +/- 4%, 40 +/- 12%, 70 +/- 5% at pH 7.4, 7.0, 6.5, respectively, the last value being reduced by cyclosporin A to 10 +/- 3%. Immunoblot method gives the similar results. It is concluded that acidification of the high phosphate medium induces release of a large part of the cytochrome c pool from liver mitochondria due to opening the Ca(2+)-dependent cyclosporin A-sensitive permeability transition pore and subsequent high amplitude swelling.
Department of Bioenergetics, A.N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow, Russia. knorre@belozersky.msu.ru
D A
DA
Knorre
V I
VI
Dedukhova
M Yu
MY
Vyssokikh
E N
EN
Mokhova
D000818:Animals; D016572:Cyclosporine / Q000494:pharmacology*; D045304:Cytochromes c / Q000032:analysis / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D015151:Immunoblotting; D007473:Ion Channels / Q000187:drug effects / Q000502:physiology*; D015636:Magnesium Chloride / Q000494:pharmacology; D008689:Methacrylates; D008930:Mitochondria, Liver / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D033681:Mitochondrial Membrane Transport Proteins; D000083162:Mitochondrial Permeability Transition Pore; D008933:Mitochondrial Swelling / Q000187:drug effects; D009243:NAD / Q000378:metabolism*; D010084:Oxidation-Reduction / Q000187:drug effects; D010101:Oxygen Consumption / Q000187:drug effects; D010710:Phosphates / Q000494:pharmacology*; D017680:Potassium Compounds / Q000494:pharmacology*; D011190:Potassium Cyanide / Q000494:pharmacology; D051381:Rats; D012402:Rotenone / Q000494:pharmacology; D013053:Spectrophotometry; D019802:Succinic Acid / Q000378:metabolism; D013844:Thiazoles / Q000494:pharmacology
D007473:Ion Channels; D008689:Methacrylates; D033681:Mitochondrial Membrane Transport Proteins; D000083162:Mitochondrial Permeability Transition Pore; D010710:Phosphates; D017680:Potassium Compounds; D013844:Thiazoles; D015636:Magnesium Chloride; D012402:Rotenone; D009243:NAD; C030517:myxothiazol; D016572:Cyclosporine; D045304:Cytochromes c; D019802:Succinic Acid; C013216:potassium phosphate; D011190:Potassium Cyanide