Regulation by the medial amygdala of copulation and medial preoptic dopamine release

The medial preoptic area (MPOA) is a critical integrative site for male cop ulatory behavior in most vertebrate species. Extracellular dopamine (DA) is increased in the MPOA of male rats immediately before and during copulatio n. DA agonists micro-injected into the MPOA of male rats facilitate and DA antagonists inhibit sexual behavior. A major source of input to the MPOA is the medial amygdala (MeA), which processes and relays olfactory informatio n to the MPOA. We now report that microinjections of a DA agonist into the MPOA of animals with excitotoxic lesions of the amygdala restored copulator y ability that was lost after the lesions. Moreover, radio-frequency lesion s of the MeA impaired copulation and blocked the increases in extracellular DA seen in animals with sham lesions during exposure to a receptive female and during copulation. Thus, both copulatory ability and the MPOA DA respo nse, during exposure to a receptive female and during copulation, are facil itated by input from the MeA to the MPOA.