Vasopressin Receptor

The neurohypophysial hormone arginine vasopressin (AVP) is involved in diverse functions including regulation of body fluid homeostasis, vasoconstriction, and adrenocorticotropic hormone release. These physiological effects are mediated by three subtypes of vasopressin receptors, designated V_1a, V_1b (or V₃), and V₂. They all belong to the large rhodopsin-like G-protein-coupled receptor family.

The V_1a receptor is expressed in both neuronal and non-neuronal tissues including the heart and elicits a variety of physiological effects including cell contraction and proliferation, stimulation of hepatic glycogenolysis, platelet aggregation and coagulation factor release. The V_1b receptor subtype is found predominantly in the pituitary gland where it stimulates adrenocorticotropic hormone release. Both the V_1a and V_1b AVP receptors act through a G protein alpha-subunit of the Gα_q family (αq, q11, q14, α15/16) to activate phospholipase C-β, and, thus enhance cellular IP3 and calcium levels. By contrast, the V₂ receptor subtype is localized predominantly to the kidney where it mediates the anti-diuretic effects of AVP through the heterotrimeric G protein Gs and activation of adenylyl cyclase.