Ghrelin augments afferent response to distension in rat isolated jejunum

Neurogastroenterol Motil. 2006 Dec;18(12):1112-20. doi: 10.1111/j.1365-2982.2006.00848.x.

Abstract

Ghrelin has been shown to decrease firing of gastric vagal afferents at doses comparable with circulating levels in the fasted state. This raises the possibility that ghrelin may have a hormonal action on other vagal afferent populations. The aim of this study was to determine the effects of ghrelin on jejunal afferent activity; including responses to distension, 2-methyl-5-hydroxytryptamine (2-methyl-5-HT) and cholecystokinin (CCK) in both naïve and vagotomized rats. Ghrelin significantly augmented the afferent response to distension. No effect was observed on baseline afferent discharge, or the response to 2-methyl-5-HT and CCK. The effect of ghrelin was more pronounced at lower ramp distending pressures (0-30 mmHg). Similarly, ghrelin augmented the jejunal afferent responses to phasic distension at 10-30 mmHg, but had no effect at higher pressures. Chronic subdiaphragmatic vagotomy and administration of the growth hormone secretagogue receptor (GHS-R) antagonist [D-Lys3]-GHRP-6 prevented the augmentation of the afferent responses to distension indicating ghrelin is acting through the GHS-R on vagal afferent fibres. Ghrelin augments the mechanosensation of jejunal vagal afferents and hence may lead to increased perception of hunger contractions.

MeSH terms

  • Animals
  • Catheterization
  • Cholagogues and Choleretics / pharmacology
  • Cholecystokinin / pharmacology
  • Compliance
  • Electrophysiology
  • Ghrelin
  • Hunger / physiology
  • In Vitro Techniques
  • Jejunum / innervation*
  • Jejunum / physiology*
  • Mechanoreceptors / drug effects
  • Mechanoreceptors / physiology
  • Oligopeptides / pharmacology
  • Peptide Hormones / pharmacology*
  • Peptide Hormones / physiology*
  • Rats
  • Rats, Sprague-Dawley
  • Serotonin / analogs & derivatives
  • Serotonin / pharmacology
  • Sodium Chloride / pharmacology
  • Vagotomy
  • Visceral Afferents / drug effects*
  • Visceral Afferents / physiology*

Substances

  • Cholagogues and Choleretics
  • Ghrelin
  • Oligopeptides
  • Peptide Hormones
  • Serotonin
  • Sodium Chloride
  • growth hormone releasing hexapeptide
  • 2-methyl-5-HT
  • Cholecystokinin