Document Detail

Hypothalamic paraventricular 5-hydroxytryptamine inhibits the effects of ghrelin on eating and energy substrate utilization.
MedLine Citation:
PMID:  20573591     Owner:  NLM     Status:  MEDLINE    
Ghrelin microinjections into discrete regions of the hypothalamus, including the paraventricular nucleus (PVN), stimulate eating and promote carbohydrate oxidation, effects similar to PVN microinjection of neuropeptide Y (NPY). We have also reported that NPY's orexigenic and metabolic effects are antagonized by pretreatment with 5-hydroxytryptamine (5-HT) or 5-HT receptor agonists. In order to determine whether 5-HT also inhibits ghrelin's orexigenic and metabolic actions, the present study examined the effects of 5-HT pretreatment on ghrelin-induced alterations in eating and energy substrate utilization following direct injections into the hypothalamic PVN. Both 5-HT (5-20 nmol) and ghrelin (100 pmol) were administered at the onset of the dark cycle. Food intake was measured 2h postinjection. A separate group of rats (n=8) was injected with 5-HT paired with ghrelin and respiratory quotient (RQ; VCO(2)/VO(2)) was measured over 2h using an open circuit calorimeter. PVN injections of ghrelin increased food intake and increased RQ, reflecting a shift in energy substrate utilization in favor of carbohydrate oxidation. 5-HT effectively blocked the effects of ghrelin on both food intake and RQ. We then administered the 5-HT(2A/2C), receptor agonist, DOI, immediately prior to ghrelin. Similar to 5-HT, PVN DOI blocked ghrelin-induced eating and inhibited the peptide's effect on substrate utilization. These data are in agreement with other evidence suggesting that ghrelin functions as a gut-brain peptide in the control of food intake and energy metabolism, and indicate that 5-HT acts within the PVN to modulate ghrelin's orexigenic and metabolic signaling.
Paul J Currie; Catherine S John; Marjorie L Nicholson; Colin D Chapman; Katherine E Loera
Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, N.I.H., Extramural     Date:  2010-06-02
Journal Detail:
Title:  Pharmacology, biochemistry, and behavior     Volume:  97     ISSN:  1873-5177     ISO Abbreviation:  Pharmacol. Biochem. Behav.     Publication Date:  2010 Nov 
Date Detail:
Created Date:  2010-10-11     Completed Date:  2011-09-15     Revised Date:  2013-05-29    
Medline Journal Info:
Nlm Unique ID:  0367050     Medline TA:  Pharmacol Biochem Behav     Country:  United States    
Other Details:
Languages:  eng     Pagination:  152-5     Citation Subset:  IM    
Copyright Information:
Copyright © 2010 Elsevier Inc. All rights reserved.
Department of Psychology, Reed College, Portland, OR 97202, USA.
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MeSH Terms
Eating / drug effects*,  physiology
Energy Metabolism / drug effects*,  physiology
Ghrelin / administration & dosage*,  antagonists & inhibitors*,  physiology
Paraventricular Hypothalamic Nucleus / drug effects*,  physiology
Rats, Sprague-Dawley
Serotonin / administration & dosage*
Substrate Specificity / drug effects,  physiology
Grant Support
070496-01A1//PHS HHS
Reg. No./Substance:
0/Ghrelin; 50-67-9/Serotonin

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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