Blockade of bombesin-like peptide receptors impairs inhibitory avoidance learning in mice

Abstract

Several studies reported that peripheral administration of bombesin (BN) and gastrin-releasing peptide (GRP) improved some forms of memory performance. In the present study, we examined the role of endogenous BN-like peptide(s) for the acquisition of inhibitory avoidance learning in mice using BN-like peptide receptor antagonists. An administration of [Leu 13-(ψ-CH 2NH)-Leu 14]BN (antagonizes GRP-R>neuromedin B receptor (NMB-R)) impaired the performance of inhibitory avoidance learning in all doses (16, 32, 64 nmol/kg). While the effect was somewhat lesser than [Leu 13-(ψ-CH 2NH)-Leu 14]BN, BIM23127 (antagonizes NMB-R>GRP-R) also impaired performance in a moderate dose (32 nmol/kg). These results showed that endogenous BN-like peptides have some role(s) for the modulation of learning and memory, and suggest that NMB/NMB-R pathway may also be involved in the memory acquisition and modulation as well as GRP/GRP-R pathway.