bradykinin receptors, member of the class A family of seven-transmembrane G protein-coupled receptors
The bradykinin receptor family is a group of the seven transmembrane G-protein coupled receptors, whose endogenous ligand is the pro-inflammatory nonapeptide bradykinin that mediates various vascular and pain responses. Two major bradykinin receptor subtypes, B1 and B2, have been identified based on their pharmacological properties. The B1 receptor is rapidly induced by tissue injury and inflammation, whereas the B2 receptor is ubiquitously expressed on many tissue types. Both receptors contain three consensus sites for N-linked glycosylation in extracellular domains and couple to G(q) protein to activate phospholipase C, leading to phosphoinositide hydrolysis and intracellular calcium mobilization. They can also interact with G(i) protein to inhibit adenylate cyclase and activate the MAPK (mitogen-activated protein kinase) pathways.