EFFECTS OF PARACHLOROPHENYLALANINE AND 5,6-DIHYDROXYTRYPTAMINE ON AGGRESSIVE-BEHAVIOR EVOKED BY CHOLINOMIMETICS AND ANTICHOLINESTERASES INJECTED INTO THE CEREBRAL-VENTRICLES OF CONSCIOUS CATS

Carbachol, muscarine, eserine and neostigmine injected into the cerebral ventricles of conscious cats, evoked emotional behaviour with aggression and autonomic and motor phenomena with clonic-tonic convulsions. The main and the most impressive feature of the gross behavioural effects of intraventricular cholinomimetics and anticholinesterases was an affective type of aggression. After 5,6-dihydroxytryptamine and parachlorophenylalanine, intraventricular carbachol, muscarine, eserine and neostigmine elicited aggression and autonomic and motor phenomena with clonic-tonic convulsions. The affective type of aggressive behaviour was modified with biting attack predominant, while hissing and snarling (i.e. vocalization) were depressed or absent. The manifestations of affective aggressive behaviour caused by muscarine were most resistent to 5,6-dihydroxytryptamine and parachlorophenylalanine. When 5-hydroxytryptophan was given to parachlorophenylalanine treated-cats, intraventricular carbachol, muscarine and eserine evoked emotional behaviour with aggression and autonomie and motor phenomena with clonic-tonic convulsions. Hissing and snarling reappeared, but they were less intense and shorter in duration than in control animals. Based on these experiments, it is concluded that an intact central 5-hydroxytryptamine network is required for the expression of emotional behavioural phenomena, especially vocalization in the appearance of the affective type of aggression. On the other hand, intact central 5-hydroxytryptamine pathways are not essential for the performance of the motor act for the attack and biting. © 1979.