Medial amygdala and aggressive behavior: Interaction between testosterone and vasopressin

This paper considers the functional significance of the testosterone-dependent vasopressinergic neurons of the medial amygdala (Ame) in intermale aggressive behavior of rats. Local microinfusion of vasopressin into the medial amygdala causes an increase in offensive behavior both in gonadally intact males and in animals that were castrated 1 week or 6 months prior to the experiment. The absolute level of offense after arginine-vasopressin (AVP) treatment declined with time after castration indicating that the behavioral consequences of AVP in the Ame are at least partially independent of testosterone. The discussion considers the possibility that AVP in the medial amygdala is involved in the modulatory role of this structure in social learning and memory processes.