Vasopressin V1b receptor (also called V3R) is a G protein-coupled receptor (GPCR) of the Gq type, thus activating the phospholipase C signaling pathway upon activation. It is part of a family of GPCRs triggered by vasopressin that further include V1R, V2R, oxytocin receptors and purinergic receptors. While V1R and V3R are Gq GPCRs, V2R is coupled to the Gs protein and activates adenylate cyclase.nThe V1b receptor has an intracellular C-terminal, seven transmembrane domains, and an extracellular N-tail; the transmembrane and extracellular domains are responsible for interacting with agonists and to signal for activation of the coupled Gq receptor
