Evidence of norepinephrine-mediated suppression of para-chlorophenylalanine-induced muricidal behavior.

Rats were made aggressive (muricide behavior) by p-chlorophenylalanine (p-CPA) treatment. The aggressive behavior was inhibited by the electrical stimulation of the locus coeruleus (LC) or by the administration of yohimbine (20 mg/kg i.p.). Both types of inhibition were blocked by the administration of low doses of clonidine (0.15 mg/kg i.p.). These results suggest the involvement of the adrenergic system in modulating muricidal behavior induced by p-CPA.