p-Chlorophenylalanine-induced muricidal aggression in male and female laboratory rats.

p-Chlorophenylalanine (pCPA), a potent inhibitor of serotonin synthesis, specifically depletes brain serotonin in a dose-dependent manner. The resulting impairment of serotonergic inhibitory control of the brain is considered responsible for the consequent muricidal aggression that arises in pCPA-treated rats independent of their strain-dependent genetic predisposition and sex propensity to display this behavior. Judging from the data obtained, the minimal impairment of serotonergic inhibitory control required to induce consistent muricidal aggression in rats of both sexes of the strains considered, corresponds to a brain serotonin depletion of about 55-60%.