6-Hydroxydopamine-induced aggression in cats: effects of various drugs

The effects of intracerebroventricular injections (ICV) in the unanesthetized cat of antimuscarinic drugs, ganglionic blocking agents, alpha and beta adrenergic blocking substances, dopamine and 5-hydroxytryptamine (5-HT) antagonists, and an antihistamine on aggressive behavior produced by 6-hydroxydopamine injected similarly was investigated. It was found that atropine, hyoscine, hexamethonium, mecamylamine, yohimbine, phenoxybenzamine, propranolol, practolol, chlorpromazine, haloperidol, antazoline and methysergide exerted virtually no effect on the pattern of aggressive responses evoked by ICV 6-hydroxydopamine. It is thus concluded that the aggressive behavior induced by 6-hydroxydopamine is not related to the release of acetylcholine, norepinephrine, dopamine, histamine or 5-hydroxytryptamine from endogenous storage sites in the brain.