Methionine-enkephalin and substance P in the basal ganglia of normals, Parkinson patients, Huntington patients, and schizophrenics. A qualitative immunohistochemical study.

The distribution of methionine-enkephalin (ME)-like and substance P (SP)-like immunoreactivity in the basal ganglia of untreated schizophrenics as compared with normal control cases, and untreated Huntington and Parkinson patients was studied using the unlabeled peroxidase-antiperoxidase (PAP) method. ME but not SP was reduced in the pallidum of one of six schizophrenics. The remaining five cases showed no differences to the controls. In contrast, no or only very faint homogeneously distributed ME and SP was found in any part of the basal ganglia in Huntington's disease. In Parkinson's disease, SP immunoreactivity was within normal range.