title: Effect of trifluoperazine on skeletal muscle mitochondrial respiration.
abstract: The effect of trifluoperazine on the respiration of porcine liver and skeletal muscle mitochondria was investigated by polarographic and spectroscopic techniques. Low concentrations of trifluoperazine (88 nmol/mg protein) inhibited both the ADP- and Ca2+-stimulated oxidation of succinate, and reduced the values of the respiratory control index and the ADP/O and Ca2+/O ratio. High concentrations inhibited both succinate and ascorbate plus tetramethyl-p-phenylenediame (TMPD) oxidations, and uncoupler (carbonyl cyanide p-trifluromethoxyphenylhydrazone) and Ca2+-stimulated respiration. Porcine liver mitochondria were more sensitive to trifluoperazine than skeletal muscle mitochondria. Trifluoperazine inhibited the electron transport of succinate oxidation of skeletal muscle mitochondria within the cytochrome b-c1 and cytochrome c1-aa3 segments of the respiratory chain system. 233 nmol trifluoperazine/mg protein inhibited the aerobic steady-state reduction of cytochrome c1 by 92% with succinate as substrate, and of cytochrome c and cytochrome aa3 by 50-60% with ascorbate plus TMPD as electron donors. Trifluoperazine can thus inhibit calmodulin-independent reactions particularly when used at high concentrations.
mesh_terms: D000244:Adenosine Diphosphate / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000494:pharmacology; D008930:Mitochondria, Liver / Q000187:drug effects; D008931:Mitochondria, Muscle / Q000187:drug effects*; D010101:Oxygen Consumption / Q000187:drug effects*; D013385:Succinate Dehydrogenase / Q000378:metabolism; D013552:Swine; D014268:Trifluoperazine / Q000494:pharmacology*
chemical_list: D014268:Trifluoperazine; D000244:Adenosine Diphosphate; D013385:Succinate Dehydrogenase; D002118:Calcium