While several DA systems exist in the brain, the mesolimbic DA system appears to be the most important in this respect. Both D1 and D2 receptors though partially functional antagonists are both significantly expressed in the NA. Other DA receptors (D3-5) are also linked to the limbic system and are substantially present in the amygdala and the hippocampus. Their functions include reward and motivation and appear to share common morphologic evolutionary and molecular roots. Endogenous opioids may also be involved in this process. Zobraziť viac o T HE R OLE OF S EXUAL A CTIVITY …