Neuropeptides in the fish gut

Summary The presence and distribution of bombesin-, enkephalin-, gastrin/cholecystokinin-, neuropeptide Y-, neurotensin-, somatostatin-, substance P-, and VIP-like immunoreactivities in gut nerves of representatives of nineteen cyclostome, elasmobranch and teleost species have been studied.The results have been correlated to results from previous studies in other species. Nerve plexuses showing bombesinlike, substance P-like and VIP-like immunoreactivity are commonly occurring, while other neuropeptides may have a more varied distribution.Tentative evolutionary patterns, and the possible function and importance of each peptide is discussed.