Effect of the general anaesthetic propanidid on oxidative phosphorylation and calcium transport in rt liver mitochondria

Action of the nonsteroidal anti-inflammatory agent, flufenamic acid, on calcium movements in isolated mitochondria

The anti-inflammatory agent flufenamic acid was found to inhibit calcium uptake in isolated mitochondria at low concentrations (IC50 = 7.2 microM). Similar concentrations were required to promote the release of calcium from mitochondria preloaded with the cation (EC50 = 3.5 microM). Identical actions were found with diflunisal, mefenanamic acid and 2,4-dinitrophenol. It was concluded that flufenamic acid was affecting calcium movements across the mitochondrial membrane by virtue of its ability to uncouple oxidative phosphorylation.

The effects of cadmium on succinate and NADH-linked substrate oxidations in rat hepatic mitochondria

Low concentrations of cadmium (3.3-40 microM) inhibited State 3 NADH-linked respiration in rat hepatic mitochondria, but failed to release oligomycin (1 microgram) inhibited State 3 respiration, or to significantly change the State 4 rate. In the presence of succinate, 40 microM cadmium inhibited State 3 respiration by 89%, while concentrations between 3.3 and 13.3 microM stimulated State 4 respiration. Higher concentrations caused marked inhibition. In the presence of succinate, cadmium released oligomycin inhibited State 3 respiration. Cadmium (0.001-1.0 mM) did not stimulate mitochondrial ATPase activity or inhibit ferricyanide reduction, but stimulated NAD+ linked mitochondrial dehydrogenase activities and NADH oxidation. These results indicate that cadmium interacts with either the NADH dehydrogenase complex or other NADH-dependent enzymes and not solely by an uncoupling action.