Peptidase-containing neurons in rat striatum.

The effects of surgical lesions on peptidase activity have been studied in the striatonigral system of the rat brain. Knife cuts separating the anterior part of the caudate putamen from the globus pallidus resulted in a decrease in the activity of angiotensin-converting enzyme and alanyl aminopeptidase in both the globus pallidus and substantia nigra. The activity of nigral prolyl endopeptidase and leucyl aminopeptidase was also decreased. An increase in dipeptidyl aminopeptidase and arginyl endopeptidase activity was observed in both the caudate putamen and globus pallidus. These results suggest that the striatal neurons containing angiotensin-converting enzyme or alanyl aminopeptidase project to both the globus pallidus and substantia nigra, and the neurons containing prolyl endopeptidase and/or leucyl aminopeptidase project to the substantia nigra. Dipeptidyl aminopeptidase and arginyl endopeptidase are probably associated with glial function.