Imidazole modification of aggressive behaviour in rats and mice.

Imidazole (IMID) strongly affected aggressive behaviour in rodents, the type of influence varying according to the experimental model considered. In morphine-dependent rats, during naloxone-induced abstinence syndrome, signs of irritability and mild aggressiveness were observed after treatment with IMID. Moreover, IMID enhanced aggressive posturing elicited by the dopaminergic (DA) agonist lisuride, whether rats were affected by morphine-withdrawal symptoms or not. In isolation test in mice, on the other hand, IMID inhibited aggression. Imidazoleacetic acid, one of the metabolites of histamine, comparatively investigated in the same behavioural tests, never potentiated lisuride-induced aggressiveness in rats; moreover, it was more effective than IMID in inhibiting aggression in isolated mice.