Central action of β-phenylethylamine derivatives (6) Head-twitches induced by intracerebrally administered tyramine in isocarboxazide pretreated mice.

Abstract

Effects of drugs on head-twitches induced by tyramine (Ty) in isocarboxazid (Iso) pretreated mice were studied. In .beta.-phenylethylamine derivatives, p-hydroxyamphetamine in non-treated and Iso-pretreated mice and Ty in Iso pretreated mice produced head-twitches. Injection of 5-HTP [5-hydroxytryptophan] (i.c. [intracerebrally] and i.p.) into mice induced head-twitches. Although head-twitches were not induced by a low dose of 5-HTP (20 mg/kg, i.p.), in Iso-pretreated mice, the number of head-twitches increased in the Iso-Ty treated group when Ty was injected i.c. in Iso + 5-HTP (20 mg/kg) pretreated mice. When Iso-Ty was injected into .alpha.-methyl-p-tyrosine pretreated mice, the number of head-twitches increased compared with Iso-Ty treated group. When Iso-Ty was injected into mice sustained with p-chlorophenylalanine, the number of head-twitches decreased compared with the Iso-Ty treated group. The number of head-twitches decreased when Iso-Ty was injected into dimetotiazine-pretreated mice; the administration of Iso-Ty in haloperidol pretreated mice had no influence on head-twitches. Serotonin is the acting mediator in the head-twitch response.