Document Detail

Involvement of the opioid system in the orexigenic and hedonic effects of melanin-concentrating hormone.
MedLine Citation:
PMID:  21775651     Owner:  NLM     Status:  Publisher    
Melanin-concentrating hormone (MCH) exerts an orexigenic effect that resembles that of opioids, suggesting that the MCH and opioid systems could interact in controlling the food intake behavior. Three series of experiments were conducted in male Wistar rats (i) to test the ability of the κ, μ and δ opioid receptor antagonists Binaltorphimine (Nor-BNI - κ), β-Funaltrexamine (β-FNA - μ), and Naltrindole (NTI - δ), respectively, to block the stimulating effects of MCH on food intake, (ii) to verify the ability of MCH to induce a positive hedonic response to a sweet stimulus, when injected into the nucleus accumbens shell (NAcSh) or right lateral ventricle (LV) of the brain, and (iii) to assess the ability of Nor-BNI, β-FNA and NTI to block the effects of MCH on the hedonic response to a sweet stimulus. Nor-BNI and NTI (0, 10 and 40 nmol) and β-FNA (0, 10 and 50 nmol) were administered into the LV prior to the LV injection of MCH (2.0 nmol). In order to assess the hedonic response, rats were also implanted with an intraoral cannula allowing for the infusion of a sweet solution into the oral cavity. Food intake was assessed in sated rats during the first three hours following the MCH or aCSF injection. The hedonic response to a sweet stimulus was assessed by examining facial mimics following an intraoral administration of a sucrose solution. The blockade of each of the three opioid receptors by selective antagonists prevents MCH-induced feeding. The results also show that MCH injected into NAcSh and LV induced an enhanced hedonic response. Moreover, antagonism of the three opioid receptors blunted LV-injected MCH-induced facial liking expressions in response to an intra-oral sweet stimulus. Overall, the present results link the MCH and opioid systems in the food intake behavior.
Carlos Andres Lopez; Benjamin Guesdon; Elena-Dana Baraboi; Boris Monge Roffarello; Marylène Hétu; Denis Richard
Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2011-7-20
Journal Detail:
Title:  American journal of physiology. Regulatory, integrative and comparative physiology     Volume:  -     ISSN:  1522-1490     ISO Abbreviation:  -     Publication Date:  2011 Jul 
Date Detail:
Created Date:  2011-7-21     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  100901230     Medline TA:  Am J Physiol Regul Integr Comp Physiol     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
1Laval University.
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