Oxidation by rat brain of N-methyl-4-phenyl-1,2,5,6-tetrahydropyridine (MPTP) coupled to tetrazolium nitro blue.

The present study shows that the dehydrogenation of N-methyl-4-phenyl-1,2,5,6-tetrahydropyridine (MPTP) can be coupled to tetrazolium nitro blue (TNB), a substance used as electron acceptor in many dehydrogenase reactions. The MPTP-TNB reductase system has an apparent Km value and inhibitor sensitivity similar to those of monoamine oxidase (MAO) type B. MPTP oxidation in the brain may very well be mediated by MAO-B.