Bombesin receptor regulation of emotional memory

Mammalian bombesin-like peptides neuromedin B (NMB) and gastrin-releasing peptide (GRP) act by activating NMB receptors (NMBR, BB1) and GRP receptors (GRPR, BB2), respectively. These two bombesin receptors are members of the G-protein-coupled receptor (GPCR) superfamily. In the brain, NMBR and GRPR are highly expressed in the brain areas involved in memory processing and emotional responses, such as the hippocampus and the amygdaloid nuclei. An increasing number of pharmacological and genetic studies in rodents indicate that NMBRs and GRPRs in brain regions including the dorsal hippocampus, the nucleus tractus solitarius, the basolateral amygdala, and cortical areas, regulate memory formation and expression, particularly for memories related to emotionally arousing tasks. GRPR signaling interacts with multiple protein kinase pathways as well as with other neurotransmitter, hormone, and growth factor systems in influencing memory formation. Together with evidence from human studies, the findings from rodent experiments suggest that bombesin receptors may be therapeutic targets in brain disorders involving memory dysfunction and anxiety.