Oxytocin Receptor

The oxytocin receptor belongs to the G-protein-coupled seven-transmembrane receptor superfamily. Its main physiological role is regulating the contraction of uterine smooth muscle at parturition and the ejection of milk from the lactating breast. The oxytocin receptors are activated in response to binding oxytocin and a similar nonapeptide, vasopressin. Oxytocin receptor triggers G_i or G_q protein-mediated signaling cascades leading to the regulation of a variety of neuroendocrine and cognitive functions.

Oxytocin is a nonapeptide of the neurohypophyseal protein family that binds specifically to the oxytocin receptor to produce a multitude of central and peripheral physiological responses. In vivo, oxytocin acts as a paracrine and/or autocrine mediator of multiple biological effects. These effects are exerted primarily through interactions with G-protein-coupled oxytocin/vasopressin receptors, which, via G_q and G_i, stimulate phospholipase C-mediated hydrolysis of phosphoinositides.