Severe aggression in rats induced by mescaline but not other hallucinogens

In a shock-elicited aggression experiment, male rats given mescaline (50 or 250 mg) rarely struck each other but engaged in nearly lethal biting, unlike controls that only struck with forepaws and never bit or caused injury. Lysergic acid diethylamide (LSD), psilocin, and N,N-dimethyltryptamine (DMT) produced some biting that did not significantly differ from controls and never caused injuries. Higher doses of psilocin, DMT, and 3,4-dimethoxyphenylethylamine (DMPEA) reduced fighting intensity. Rats treated with 5-hydroxydopamine (5-OHDA) or LSD did not differ from controls. Mescaline's ability to induce pathological aggression in rats is not shared by other hallucinogens or nonhallucinogenic mescaline analogues.

Study at a glance

Abstract

Pairs of male Sprague-Dawley rats were administered mescaline, lysergic acid diethylamide (LSD), psilocin, N,N-dimethyltryptamine (DMT), 3,4-dimethoxyphenylethylamine (DMPEA), or 5-hydroxydopamine (5-OHDA) IP prior to being placed in a shock-elicited aggression situation. When foot shock was delivered, controls struck each other with their forepaws, but never engaged in either biting or injurious fighting. Mescaline-treated rats (50 or 250 mg) rarely struck each other, but engaged in nearly lethal biting. While LSD (25--400 micrograms/kg), psilocin (2.0 mg/kg), and DMT (5 mg/kg) produced some biting, this did not significantly differ from controls and never resulted in injuries. At higher doses, psilocin, DMT, and DMPEA decreased the amount and intensity of fighting. Rats treated with 5-OHDA (8--200 mg/kg) or LSD (25--400 micrograms/kg) did not differ from controls. These results suggest that mescaline's ability to induce pathological aggression in rats exposed to foot shock is not shared by other hallucinogens or nonhallucinogenic mescaline analogues.