title: Inhibition of mitochondrial NADH-ubiquinone oxidoreductase activity by 1-methyl-4-phenylpyridinium ion.
abstract: Effect of 1-methyl-4-phenylpyridinium ion (MPP+) on the activity of NADH-ubiquinone oxidoreductase was studied using mitochondria prepared from rat brains. At first, inhibition of oxygen consumption by MPP+ with pyruvate + malate or glutamate + malate as substrates was confirmed polarographically using a Clark-type oxygen electrode. Then, activity of NADH-ubiquinone oxidoreductase in the same samples used in polarography was assayed. Incubation of mitochondria with 0.05 mM of MPP+ together with glutamate, malate and ADP resulted in approximately 50% inhibition of NADH-ubiquinone oxidoreductase activity. Significance of the results was discussed with respect to the mechanism of neuronal degeneration by MPP+.
mesh_terms: D015655:1-Methyl-4-phenylpyridinium; D000818:Animals; D001921:Brain / Q000201:enzymology*; D005615:Freezing; D007700:Kinetics; D008297:Male; D008928:Mitochondria / Q000187:drug effects / Q000201:enzymology* / Q000378:metabolism; D016660:NAD(P)H Dehydrogenase (Quinone); D009498:Neurotoxins / Q000494:pharmacology*; D010101:Oxygen Consumption / Q000187:drug effects; D011726:Pyridinium Compounds / Q000494:pharmacology*; D011808:Quinone Reductases / Q000037:antagonists & inhibitors*; D051381:Rats; D011916:Rats, Inbred F344
chemical_list: D009498:Neurotoxins; D011726:Pyridinium Compounds; D016660:NAD(P)H Dehydrogenase (Quinone); D011808:Quinone Reductases; D015655:1-Methyl-4-phenylpyridinium