Document Detail

Ghrelin interacts with neuropeptide Y Y1 and opioid receptors to increase food reward.
MedLine Citation:
PMID:  22210742     Owner:  NLM     Status:  MEDLINE    
Ghrelin, a stomach-derived hormone, is an orexigenic peptide that was recently shown to potently increase food reward behavior. The neurochemical circuitry that links ghrelin to the mesolimbic system and food reward behavior remains unclear. Here we examined the contribution of neuropeptide Y (NPY) and opioids to ghrelin's effects on food motivation and intake. Both systems have well-established links to the mesolimbic ventral tegmental area (VTA) and reward/motivation control. NPY mediates the effect of ghrelin on food intake via activation of NPY-Y1 receptor (NPY-Y1R); their connection with respect to motivated behavior is unexplored. The role of opioids in any aspect of ghrelin's action on food-oriented behaviors is unknown. Rats were trained in a progressive ratio sucrose-induced operant schedule to measure food reward/motivation behavior. Chow intake was measured immediately after the operant test. In separate experiments, we explored the suppressive effects of a selective NPY-Y1R antagonist or opioid receptor antagonist naltrexone, injected either intracerebroventricularly or intra-VTA, on ghrelin-induced food reward behavior. The ventricular ghrelin-induced increase in sucrose-motivated behavior and chow intake were completely blocked by intracerebroventricular pretreatment with either an NPY-Y1R antagonist or naltrexone. The intra-VTA ghrelin-induced sucrose-motivated behavior was blocked only by intra-VTA naltrexone. In contrast, the intra-VTA ghrelin-stimulated chow intake was attenuated only by intra-VTA NPY-Y1 blockade. Finally, ghrelin infusion was associated with an elevated VTA μ-opioid receptor expression. Thus, we identify central NPY and opioid signaling as the necessary mediators of food intake and reward effects of ghrelin and localize these interactions to the mesolimbic VTA.
Karolina P Skibicka; Rozita H Shirazi; Caroline Hansson; Suzanne L Dickson
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2011-12-30
Journal Detail:
Title:  Endocrinology     Volume:  153     ISSN:  1945-7170     ISO Abbreviation:  Endocrinology     Publication Date:  2012 Mar 
Date Detail:
Created Date:  2012-02-22     Completed Date:  2012-04-16     Revised Date:  2014-03-25    
Medline Journal Info:
Nlm Unique ID:  0375040     Medline TA:  Endocrinology     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1194-205     Citation Subset:  AIM; IM    
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MeSH Terms
Animal Feed
Feeding Behavior
Ghrelin / metabolism*
Infusions, Intraventricular
Models, Biological
Naltrexone / pharmacology
Narcotic Antagonists / pharmacology
Rats, Sprague-Dawley
Receptors, Neuropeptide Y / chemistry*
Receptors, Opioid, mu / metabolism*
Sucrose / chemistry,  metabolism
Ventral Tegmental Area / metabolism
Reg. No./Substance:
0/Ghrelin; 0/Narcotic Antagonists; 0/Receptors, Neuropeptide Y; 0/Receptors, Opioid, mu; 0/neuropeptide Y-Y1 receptor; 57-50-1/Sucrose; 5S6W795CQM/Naltrexone

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