title: Glucagon-like peptide (GLP-1) is involved in the central modulation of fecal output in rats.
abstract: In addition to its insulinotropic action, exogenously administered glucagon-like peptide (GLP-1) inhibits gastropancreatic motility and secretion via central pathways. The aims of the present study were to evaluate the effects of exogenous GLP-1-(7-36) amide on fecal output and to investigate the role of endogenous GLP-1 on stress-induced colonic activity. With the use of a stereotaxic instrument, adult male Sprague-Dawley rats weighing 200-250 g were fitted with stainless steel cerebroventricular guide cannulas under ketamine anesthesia. A group of rats were placed in Bollman-type cages to induce restraint stress. Fecal output monitored for 2 h was increased significantly by intracerebroventricular GLP-1 to 500, 1, 000, and 3,000 pmol/rat (P < 0.05-0.01), whereas intraperitoneal GLP-1 had no effect. Intracerebroventricular administration of the GLP-1 receptor antagonist exendin-(9-39) (10 nmol/rat) reversed the increases induced by GLP-1 (500 pmol/rat; P<0.01). Similar results were also observed with the injection of corticotropin-releasing factor receptor antagonist astressin (10 microg/rat icv). The significant increase in fecal pellet output induced by restraint stress was also decreased by both intracerebroventricular exendin (10 nmol/rat) and astressin (10 microg/rat; P<0.01-0.001). These results suggest that GLP-1 participates in the central, but not peripheral, regulation of colonic motility via its own receptor and that GLP-1 is likely to be a candidate brain-gut peptide that acts as a physiological modulator of stress-induced colonic motility.
authors.affiliation: Department of Physiology, Marmara University, School of Medicine, Haydarpaşa 81326, stanbul, Turkey.
authors.forename: M A
authors.initials: MA
authors.lastname: Gülpinar
authors.forename: A
authors.initials: A
authors.lastname: Bozkurt
authors.forename: T
authors.initials: T
authors.lastname: Coşkun
authors.forename: N B
authors.initials: NB
authors.lastname: Ulusoy
authors.forename: B C
authors.initials: BC
authors.lastname: Yegen
mesh_terms: D000818:Animals; D001921:Brain / Q000502:physiology*; D003346:Corticotropin-Releasing Hormone / Q000494:pharmacology; D003672:Defecation / Q000187:drug effects / Q000502:physiology*; D005934:Glucagon / Q000494:pharmacology / Q000502:physiology*; D052216:Glucagon-Like Peptide 1; D000067757:Glucagon-Like Peptide-1 Receptor; D007274:Injections, Intraperitoneal; D007276:Injections, Intraventricular; D008297:Male; D010446:Peptide Fragments / Q000494:pharmacology / Q000502:physiology*; D011498:Protein Precursors / Q000494:pharmacology / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D018027:Receptors, Glucagon / Q000037:antagonists & inhibitors; D012149:Restraint, Physical; D013312:Stress, Physiological / Q000503:physiopathology
chemical_list: C000593835:Glp1r protein, rat; D000067757:Glucagon-Like Peptide-1 Receptor; D010446:Peptide Fragments; D011498:Protein Precursors; D018027:Receptors, Glucagon; C104416:astressin; C083773:exendin (9-39); D052216:Glucagon-Like Peptide 1; D005934:Glucagon; D003346:Corticotropin-Releasing Hormone