Actions of neuromedin-B and neuromedin-C on amylase release from isolated rat pancreatic acini.
Neuromedin-B and neuromedin-C are novel decapeptides which have recently been isolated from porcine spinal cord and canine intestinal muscle, and show striking sequence homology with gastrin-releasing peptide (GRP-27) at the carboxyl-terminal region. The effects of synthetic neuromedin-B and neuromedin-C on exocrine pancreatic function were examined using isolated rat pancreatic acini. Neuromedin-B and neuromedin-C were able to cause full stimulation of amylase release. The relative efficacy of neuromedin-B and neuromedin-C was the same as that of GRP-27. Neuromedin-C was about twofold more potent, whereas, neuromedin-B was about 10-fold less potent than GRP-27. Both neuromedin-B and neuromedin-C potentiated the stimulation of amylase release caused by vasoactive intestinal peptide, secretin, or forskolin. Potentiation of amylase secretion did not occur with neuromedin-B or neuromedin-C plus cholecystokinin (CCK), carbamylcholine, or Ca2+ ionophore A23187. The effects of neuromedin-B and neuromedin-C on enzyme secretion were inhibited neither by dibutyryl cyclic GMP, nor atropine. The present study suggests that neuromedin-B and neuromedin-C act on different receptors than CCK and cholinergic agents, but appear to activate a common intracellular mechanism.
D000681:Amylases / Q000378:metabolism*; D000818:Animals; D001839:Bombesin / Q000494:pharmacology*; D019886:Gastrin-Releasing Peptide; D066298:In Vitro Techniques; D008297:Male; D015287:Neurokinin B / Q000031:analogs & derivatives*; D009479:Neuropeptides / Q000494:pharmacology*; D010179:Pancreas / Q000187:drug effects* / Q000378:metabolism; D010446:Peptide Fragments / Q000494:pharmacology*; D010455:Peptides / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D012844:Sincalide / Q000494:pharmacology
D009479:Neuropeptides; D010446:Peptide Fragments; D010455:Peptides; D019886:Gastrin-Releasing Peptide; C040794:neuromedin C; D015287:Neurokinin B; C038393:neuromedin B; D000681:Amylases; D012844:Sincalide; D001839:Bombesin