Behavioural effects of acute and chronic beta-phenylethylamine administration in the rat: evidence for the involvement of 5-hydroxytryptamine.

The behavioural consequences of daily beta-phenylethylamine (PEA) administration for a period of 6 weeks have been examined. Rats first showed signs of the 5-HT behavioural syndrome after a single injection of PEA (50mg/kg) or 7 daily injections of PEA (25mg/kg). The syndrome reached peak intensity after 3 weeks treatment and was prevented by pre-treatment with 5-HT antagonists mianserin and methysergide or the neuroloptic clozapine but relatively unaffected by pre-treatment with haloperidol. These data provide strong evidence for an effect of PEA on brain 5-HT mechanisms. Because of the similarity between PEA and amphetamine and the suggestion that PEA may be involved in the aetiology of schizophrenia, it is proposed that the mechanisms of action of PEA be reassessed taking into account its ability to affect 5-HT systems in addition to catecholaminergic systems.