Dopamine agonist-induced penile erection and yawning: Differential role of D2-like receptor subtypes and correlation with nitric oxide production in the paraventricular nucleus of the hypothalamus of male rats

► Dopamine D2-like agonists induce penile erection and yawning in rats/humans. ► A site of action of D2-like agonists is the paraventricular nucleus of the hypothalamus (PVN). ► These behavioral responses of D2 agonists are secondary to an increased PVN NO production. ► These responses are mainly due to the stimulation of D2, but not D3 or D4 receptors. ► Stimulation of PVN D4 receptors also increases NO production and penile erection, but not yawning.