Cheah K S, Waring J C
Biochim Biophys Acta. 1983 Apr 22;723(1):45-51. doi: 10.1016/0005-2728(83)90007-5.
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.
