Effects of histaminergic drugs on muricide induced by thiamine deficiency.

Male Wistar rats maintained on a thiamine deficient diet showed mouse-killing aggression (muricide). On the 30th day of experimental feeding, the incidence of this muricide was about 70%. Intracerebroventricular histamine suppressed the muricide induced by thiamine deficiency in a dose-dependent manner. Histamine H1-receptor blocking agents such as diphenhydramine, promethazine and chlorpheniramine also showed muricidal suppression, but astemizole which lacks central effects did not show muricidal suppression. Mianserin and iprindole showed muricidal suppression, but metiamide i.p. did not. On the 20th day of experimental feeding, the incidence of this muricide was 45.5%. Histamine synthesis inhibitors such as brocresine or alpha-fluoromethylhistidine could not enhance the muricide on non-killer-rats, but really suppressed the thiamine deficient killer-rats. The results of this paper suggested that muricide induced by thiamine deficiency is not mediated by the central histaminergic system, but pharmacologically characterized by antidepressants, antihistamines and histamine synthesis inhibitors.