Effect of synthetic neuromedin C, a decapeptide of gastrin-releasing peptide (GRP [18-27]), on blood flow and exocrine secretion of the pancreas in dogs

Neuromedin C, the smaller molecular form of gastrin releasing peptide (GRP [18-27]), has been recently identified from canine intestinal muscle and porcine spinal cord. This study was conducted to determine if this newly identified peptide retains biological activity on canine pancreas in vivo. Intravenous injection of graded doses of synthetic Neuromedin C caused a marked increase of systemic blood pressure and initial reduction of pancreatic blood flow in eleven anesthetized dogs, as measured by Laser Doppler Flowmetry. Flow volume and protein output of pancreatic juice were also increased by Neuromedin C in a dose-related manner in six dogs. These results suggest that this peptide is one of the biologically active forms of mammalian bombesin-like peptides and may possess physiological significance as a novel neuropeptide.     

Chemical specificity of short-chain fatty acid-induced electrogenic secretory response in the rat colonic mucosa

1. Luminal additions of normal short-chain fatty acids (SCFA: 3-6 carbons) increased transmural potential difference (PD: lumen negative) across rat everted colon in a dose-dependent manner. 2. The PD response to SCFA adapted rapidly and was not evoked by further cumulative addition of the same acid (self-adaptation) or different acids (cross-adaptation). 3. A broad range of SCFA derivatives were tested as potential stimulators of the PD response and cross-adaptation with propionate: a single carboxyl group and 3-6 carbon-chain were an absolute requirement for recognition. 4. These results suggest that SCFA-reception mechanism of the rat colonic mucosa has some sort of chemical specificity for stimulating electrogenic secretory response.