Bombesin receptor (BnR (or BB receptor for subtypes))

The **bombesin receptor** is a member of the G protein-coupled receptor (GPCR) family comprising three main subtypes in mammals: Neuromedin B receptor (NMBR/BB1), Gastrin-releasing peptide receptor (GRPR/BB2), and Bombesin receptor subtype-3 (BRS-3/BB3)[1][2][4][5][6]. These receptors are widely expressed in the central nervous system and peripheral tissues. They play diverse roles in physiological processes—regulating smooth muscle contraction, cell growth, secretion, feeding behavior, and immune responses[1][2][4][5][6]. Bombesin and homologous peptides (gastrin-releasing peptide, neuromedin B) act as endogenous ligands for these receptors. Notably, bombesin receptors are frequently overexpressed in certain cancers and are being investigated as targets for tumor imaging and therapeutic interventions[2][5][6]. While BRS-3 remains an orphan receptor with unknown endogenous ligand, BB1 and BB2 are functionally well-characterized. The broad biological distribution and significant involvement in disease processes underscore their clinical importance.

Other names

BB receptorBB1 receptor (Neuromedin B receptor/NMBR)BB2 receptor (Gastrin-releasing peptide receptor/GRPR)BB3 receptor (Bombesin receptor subtype-3/BRS-3)Bombesin-like peptide receptorBombesin receptor family

Antagonism or agonism at bombesin receptor subtypes leading to modulation of GPCR-mediated signaling pathways; blockage suppresses cell proliferation/growth in bombesin-dependent tumors; agonism induces signal cascades via Gq/11 proteins and phospholipase C activation[2][5][6]