“Methamphetamine-stereotypies” and brain dopamine levels of rats treated with single or repeated doses of α-methyl-para-tyrosine.

Abstract

Male albino Wistar rats were injected intraperitoneally with saline solution (1.0 ml/kg) or a-methyl-paratyrosine (50mg/kg) once or daily X 7 and methamphetamine (10 mg/kg) was injected 3 hr or 24 hr after the last injection of these drugs. Stereotyped licking and biting activity were scored during 120 min after methamphetamine injection and, in parallel brain dopamine levels were measured. Methamphetamine given 3 hr after single or repeated administrations of α-methyl-para-tyrosine was not effective for stereotyped behavior and brain dopamine levels in similarly treated rats decreased markedly in comparison with saline-treated rats. Methamphetamine 24 hr after repeated administration of α-methyl-para-tyrosine clearly induced stereotypies and brain dopamine levels in these rats did not differ From saline-treated rats. The results suggest a possible role of brain dopamine on “methamphetamine-stereotypies”.