title: Down-regulation of ghrelin receptors in the small intestine delays small intestinal transit in vagotomized rats.
abstract: Vagal nerve injury may occur in esophageal and gastric surgeries. The aim of this study was to observe the effects of ghrelin on small intestinal motility upon vagal nerve injury and the possible co-relationship between changes in ghrelin receptor expression in the small intestine and delayed small intestinal transit after vagotomy. The effects of intraperitoneal administration of ghrelin (20, 40 and 80 µg/kg) and the ghrelin receptor antagonist [D-Lys3]-GHRP-6 (1.5 µmol/kg) on small intestinal transit were studied in control and vagotomized rats in vivo. The effects of ghrelin (0.01, 0.1, 0.5, 1.0 and 2.0 µmol/l) on the contraction force of smooth muscle strips from the jejunum were studied in the presence or absence of carbachol (50 nmol/l) and [D-Lys3]-GHRP-6 (10 µmol/l) in vitro. Ghrelin receptor expression was assessed in intestinal muscle layers by means of Western blotting. The results indicated that ghrelin dose-dependently increased small intestinal transit in the control and model rats. In addition, ghrelin enhanced smooth muscle strip contraction induced by carbachol. Ghrelin receptor antagonist [D-Lys3]-GHRP-6 blocked the effect of ghrelin. Ghrelin receptor expression in the small intestinal muscle layers was down-regulated in the vagotomized rats. Down-regulation of growth hormone secretagogue receptor 1a in small intestinal muscle layers, which affected the function of ghrelin, may be one of the mechanisms behind delayed small intestinal transit after vagotomy.
authors.affiliation: Department of General Surgery, The Sixth Hospital Affiliated with Shanghai Jiao Tong University, Shanghai 200233, PR China.
authors.forename: Cheng-Guang
authors.initials: CG
authors.lastname: Yang
authors.forename: Wen-Cai
authors.initials: WC
authors.lastname: Qiu
authors.forename: Zhi-Gang
authors.initials: ZG
authors.lastname: Wang
authors.forename: Song
authors.initials: S
authors.lastname: Yu
authors.forename: Jun
authors.initials: J
authors.lastname: Yan
authors.forename: Qi
authors.initials: Q
authors.lastname: Zheng
mesh_terms: D000818:Animals; D002217:Carbachol / Q000494:pharmacology; D004195:Disease Models, Animal; D015536:Down-Regulation; D005769:Gastrointestinal Motility / Q000187:drug effects*; D054439:Ghrelin / Q000494:pharmacology; D007421:Intestine, Small / Q000378:metabolism*; D008297:Male; D009842:Oligopeptides / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D054440:Receptors, Ghrelin / Q000037:antagonists & inhibitors / Q000378:metabolism*; D014628:Vagotomy; D061223:Vagus Nerve Injuries / Q000378:metabolism* / Q000473:pathology
chemical_list: C520836:GHRP-6, Lys(3)-; D054439:Ghrelin; D009842:Oligopeptides; D054440:Receptors, Ghrelin; D002217:Carbachol