FIG. 4.

SS-31 and SS-20 reduced MPP⁺-induced inhibition of mitochondrial oxygen consumption and ATP production. Isolated mouse liver mitochondria were incubated in respiratory buffer and oxygen consumption was measured by a Clark-type oxygen electrode. State 3 respiration was initiated by the addition of ADP. Co-incubation with 50 μM SS-31 or 10 μM and 50 μM SS-20 significantly attenuated the inhibition of oxygen consumption induced by 100 μM MPP⁺. ATP production was determined by using luciferase bioluminescent assay. Co-incubation with both doses of 10 μM and 50 μM of either SS-31 or SS-20 significantly attenuated the inhibition of ATP production induced by 100 μM MPP⁺. *p < 0.05; **p < 0.01 compared to treatment with MPP⁺ alone. Incubation with SS-31 or SS-20 alone did not alter oxygen consumption and ATP production (data not shown).