1-METHYL-4-PHENYLPYRIDINIUM (MPP(-CONSUMPTION MEDIATED BY SUCCINATE AS WELL AS MALATE IN RAT PHEOCHROMOCYTOMA PC12 CELLS()) INHIBITS MITOCHONDRIAL OXYGEN)

When rat pheochromocytoma PC12 cells are cultured with 1 mM 1-methyl-4 -phenylpyridinium (MPP(+)), the number of viable cells decreases to on e third in 4 days while the number increases ten-fold without MPP(+). Oxygen consumption by mitochondria in the presence of malate is inhibi ted about 80 % by the treatment of the cells with MPP(+) for 4 days. U nexpectedly, succinate-dependent oxygen consumption is also inhibited to essentially the same extent as malate-dependent one. These results suggest that the impairment of the respiration mediated by succinate a s well as malate is important as a mechanism of MPP(+)-induced cell de ath.