The ability of a selective neuromedin B receptor antagonist, D-Nal-cyclo[Cys-Tyr-D-Trp-Orn-Val-Cys]-Nal-NH2 (BIM-23127), to block suppression of food intake produced by the mammalian bombesin-like peptides neuromedin B and neuromedin C was examined. BIM-23127 completely blocked suppression of intake produced by neuromedin B but not by neuromedin C. These results suggest an independent role for neuromedin B receptors in suppression of food intake by bombesin-like peptides and demonstrate the utility of this group of antagonists for in vivo experiments.