A new putative neuroregulator of the extrapyramidal system.

A putative neurotransmitter, 2-phenylethylamine, which is most highly concentrated in the extrapyramidal system of human brain, is able to reverse reserpine-induced parkinsonism in animals and elicit stereotypy. This action is only partially antagonized after catecholamine depletion by pretreatment with a-methyl-para-tyrosine, and fully blocked by pretreatment with haloperidol, a dopamine receptor blocker. Therefore, via direct and/or indirect actions, 2-phenylethylamine may serve a neuroregulatory role in the extrapyramidal system.