The gastric CB1 receptor modulates ghrelin production through the mTOR pathway to regulate food intake

PLoS One. 2013 Nov 26;8(11):e80339. doi: 10.1371/journal.pone.0080339. eCollection 2013.

Abstract

Over the years, the knowledge regarding the relevance of the cannabinoid system to the regulation of metabolism has grown steadily. A central interaction between the cannabinoid system and ghrelin has been suggested to regulate food intake. Although the stomach is the main source of ghrelin and CB1 receptor expression in the stomach has been described, little information is available regarding the possible interaction between the gastric cannabinoid and ghrelin systems in the integrated control of energy homeostasis. The main objective of the present work was to assess the functional interaction between these two systems in terms of food intake using a combination of in vivo and in vitro approaches. The present work demonstrates that the peripheral blockade of the CB1 receptor by rimonabant treatment decreased food intake but only in food-deprived animals. This anorexigenic effect is likely a consequence of decreases in gastric ghrelin secretion induced by the activation of the mTOR/S6K1 intracellular pathway in the stomach following treatment with rimonabant. In support of this supposition, animals in which the mTOR/S6K1 intracellular pathway was blocked by chronic rapamycin treatment, rimonabant had no effect on ghrelin secretion. Vagal communication may also be involved because rimonabant treatment was no longer effective when administered to animals that had undergone surgical vagotomy. In conclusion, to the best of our knowledge, the present work is the first to describe a CB1 receptor-mediated mechanism that influences gastric ghrelin secretion and food intake through the mTOR pathway.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cannabinoids / metabolism
  • Cannabinoids / pharmacology
  • Feeding Behavior*
  • Gastric Mucosa / metabolism
  • Gene Expression
  • Ghrelin / biosynthesis*
  • Ghrelin / blood
  • Ghrelin / genetics
  • Ghrelin / pharmacology
  • Immunohistochemistry
  • Male
  • Piperidines / pharmacology
  • Pyrazoles / pharmacology
  • Rats
  • Receptor, Cannabinoid, CB1 / antagonists & inhibitors
  • Receptor, Cannabinoid, CB1 / genetics
  • Receptor, Cannabinoid, CB1 / metabolism*
  • Rimonabant
  • Signal Transduction* / drug effects
  • TOR Serine-Threonine Kinases / metabolism*

Substances

  • Cannabinoids
  • Ghrelin
  • Piperidines
  • Pyrazoles
  • Receptor, Cannabinoid, CB1
  • TOR Serine-Threonine Kinases
  • Rimonabant

Grants and funding

This research has been funded by Instituto de Salud Carlos III ( PS09/02075 and PI1202021); Xunta de Galicia (10 PXIB 918 273PR) Fundación Mutua Madrileña. Centro de Investigacion Biomedica en Red Fisiopatología de la Obesidad y Nutrición is an ISCIII iniciative (CB06/03). CC is funded by CIBER Fisiopatología Obesidad y Nutrición (CB06/03), LLS is funded by the University Professional Development Program (FPU) of the Spanish Ministry of Education, SB-F by Xunta de Galicia. The funders had no role in study design, data collection and analysis, decision to publish or preparation of the manuscript.