Acute neuropathological changes in the caudate nucleus caused by MPTP and methamphetamine: immunohistochemical studies.

Three days after the administration of MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) or methamphetamine to mice, there is degeneration and disappearance of punctate tyrosine hydroxylase-containing synaptic endings in the caudate nucleus. The neuropil is occupied with longer, varicose, branching fibres, which appear to be preterminal fibres. An intense gliosis occurs. The sparsely-occurring glial cells, with profuse lightly-stained (by glial fibrillary acidic protein) processes which are primarily located near blood vessels, become transformed into more heavily-stained star-shaped cells with fewer but thicker processes. These cells are distributed throughout the caudate. Despite apparent differences in the mechanism by which MPTP and methamphetamine cause dopamine depletion, the neuropathological changes in the caudate induced by these substances are identical.