Document Detail


Energetic responses are triggered by caudal brainstem melanocortin receptor stimulation and mediated by local sympathetic effector circuits.
MedLine Citation:
PMID:  18372329     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The central melanocortin system is a critical contributor to energy balance control. Melanocortin receptors (MC-Rs) are widely distributed throughout forebrain and caudal brainstem nuclei. To assess the contribution of hindbrain MC-Rs to the control of energy expenditure, the MC3/4R agonist melanotan II (MTII) was delivered to either the fourth ventricle or medullary raphe of neurologically intact rats and chronic decerebrate (CD) rats, and interscapular brown adipose tissue (IBAT) temperature (T(IBAT)), core temperature (T(C)), heart rate (HR), and spontaneous activity were recorded. Fourth ventricular MTII (0.1, 1.0 nmol) significantly increased T(IBAT), T(C), and HR in intact rats (T(C): +0.33 +/- 0.08, +0.41 +/- 0.09 C; HR: +40.84 +/- 7.29, +69.04 +/- 6.83 beats per minute) and in CDs (T(C): +1.39 +/- 0.67, +1.52 +/- 0.37 C; HR: +83.21 +/- 19.2, +107.38 +/- 17.65 beats per minute). Response magnitude was greater in CD rats than in neurologically intact rats. T(IBAT), T(C), and HR were significantly increased after 10 pmol MTII delivery to the medullary raphe of intact rats, and here too, the response magnitude was greater in decerebrate rats. The hyperthermia, IBAT thermogenesis, and tachycardia observed in CD rats after fourth ventricular and hindbrain parenchymal MTII injections support the hypothesis that hindbrain MC-R stimulation engages endemic circuits that link sympathetic outflows to thermogenic and cardiac effectors, and that forebrain processing and forebrain-caudal brainstem communication are not required for response production.
Authors:
Karolina P Skibicka; Harvey J Grill
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural     Date:  2008-03-27
Journal Detail:
Title:  Endocrinology     Volume:  149     ISSN:  0013-7227     ISO Abbreviation:  Endocrinology     Publication Date:  2008 Jul 
Date Detail:
Created Date:  2008-06-30     Completed Date:  2008-09-22     Revised Date:  2009-11-18    
Medline Journal Info:
Nlm Unique ID:  0375040     Medline TA:  Endocrinology     Country:  United States    
Other Details:
Languages:  eng     Pagination:  3605-16     Citation Subset:  AIM; IM    
Affiliation:
Graduate Group of Psychology and Graduate Group of Neuroscience, University of Pennsylvania, Philadelphia, PA 19104, USA. skibicka@mail.med.upenn.edu
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MeSH Terms
Descriptor/Qualifier:
Adipose Tissue, Brown / drug effects,  metabolism
Animals
Body Temperature / drug effects
Brain Stem / drug effects,  metabolism
Energy Metabolism / drug effects*
Heart Rate / drug effects
Male
Peptides, Cyclic / pharmacology*
Prosencephalon / drug effects,  metabolism
Rats
Rats, Sprague-Dawley
Receptor, Melanocortin, Type 3 / agonists,  metabolism,  physiology
Receptor, Melanocortin, Type 4 / agonists,  metabolism,  physiology
Receptors, Melanocortin / agonists*,  metabolism,  physiology
Rhombencephalon / drug effects,  metabolism
Sympathetic Nervous System / drug effects*,  physiology
alpha-MSH / analogs & derivatives*,  pharmacology
Grant Support
ID/Acronym/Agency:
DK 21397/DK/NIDDK NIH HHS; T32 GM 07517/GM/NIGMS NIH HHS
Chemical
Reg. No./Substance:
0/Peptides, Cyclic; 0/Receptor, Melanocortin, Type 3; 0/Receptor, Melanocortin, Type 4; 0/Receptors, Melanocortin; 121062-08-6/melanotan-II; 581-05-5/alpha-MSH
Comments/Corrections

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