Regional localization of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) uptake: mismatch between its uptake and neurotoxic sites.

Three to 24 h following intraventricular injections of radioactive 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) into the rat, accumulations of radiolabel were widely detected, in varying degree, over neuronal perikarya in motor-related structures below the midbrain. Pretreatment with the monoamine oxidase B inhibitor pargyline largely eliminated the perikaryal radiolabeling in the substantia nigra, dorsal raphe and cerebellum, leaving that in the other regions intact. These results indicate that there exists a certain mismatch between MPTP uptake and neurotoxic sites, and that invulnerable cells can accumulate MPTP without being converted to its major active metabolite 1-methyl-4-phenylpyridine (MPP+).