Effects of chronic administration of antidepressants on mouse-killing behavior (muricide) in olfactory bulbectomized rats.

Two forms of drug administration, i.e., systemic subcutaneous administration and microinjection into the medial amygdala were employed to examine the effect of chronic administration of psychotropic drugs on muricide in olfactory bulbectomized rats. Muricide inhibition induced by the systemic doses of chlorpromazine (CPZ) 10 mg/kg and diazepam 10 mg/kg was reduced with chronic administration, while that by desipramine (DMI) 10 mg/kg and amitriptyline 30 mg/kg was augmented with chronic administration. Muricide inhibition induced by microinjection of CPZ was also reduced, while that by DMI was augmented. These results indicate that muricide by olfactory bulbectomized rats is a useful animal model for evaluating antidepressants and that a potential site of action of antidepressants is located in the medial amygdala.