The histochemical demonstration of MPTP oxidation in the postmortem human striatum.

Monoamine oxidase (MAO) histochemistry has been performed in postmortem human striatal tissues using 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) as substrate. The reaction products of MPTP oxidation in the human putamen and caudate nucleus were observed in glial cells. Although glial staining was found diffusely in the human striatum, prominently intense staining was observed in glial cells surrounding vessels. Double staining for MAO and glial fibrillary acidic protein showed that glial cells containing MAO activity were astrocytes. The inhibition experiments using clorgyline and 1-deprenyl as MAO inhibitors indicate that MAO associated with the present MPTP oxidation was of the B type. The present observations suggest that astrocytes, especially around vessels, may be involved in MPTP oxidation in the human striatum after systemic administration of MPTP.