The effects of metoclopramide, sulpiride, and the stereoisomers of baclofen on amphetamine-induced behavior in the marmoset.

We have studied the effects on amphetamine-induced behavior in a primate species of drugs (other than the classic neuroleptics) sometimes used in the treatment of psychosis. Marmosets were treated with either saline (control animals) or amphetamine followed after 18 min by doses of either metoclopramide, sulpiride, or the d- or l-isomers of baclofen. Metoclopramide antagonized amphetamine-induced behavior at low doses while also causing sedation at higher doses in control animals. Neither sulpiride nor baclofen specifically antagonized amphetamine-induced behavior.