Document Detail

Depletion of brown fat norepinephrine content by acute cold exposure and adrenoceptor blockade.
MedLine Citation:
PMID:  11325417     Owner:  NLM     Status:  MEDLINE    
Experiments were conducted to characterize the effects of acute cold exposure, with and without adrenoceptor blockade, on intrascapular brown adipose tissue (IBAT) and adrenal catecholamine content in male Sprague-Dawley rats. Groups of animals with indwelling temperature transmitters were tested following treatment with saline, the alpha-adrenoceptor blocker phentolamine, the beta-adrenoceptor blocker propranolol, combined blockade with phentolamine plus propranolol, and the ganglionic blocker chlorisondamine. IBAT norepinephrine (NE) content was not affected in animals tested at 22 degrees C, but was reduced in 4 degrees C-exposed animals treated with phentolamine (-57%), phentolamine plus propranolol (-97%), and chlorisondamine (-42%). Adrenal NE and epinephrine (EPI) content were not altered by the treatments at 4 degrees C or 22 degrees C. None of the treatments affected the temperature of animals at 22 degrees C, but significant hypothermia occurred at 4 degrees C after chlorisondamine (-2.3+/-0.3 degrees C) and the combination of phentolamine and propranolol (-1.5+/-0.4 degrees C). These results suggest that cold exposure alone did not affect IBAT NE content, but when cold exposure was combined with adrenoceptor blockade, the sympathetic activation was sufficient to cause a reduction in IBAT NE content. In addition, alpha- and beta-adrenoceptor-mediated mechanisms contribute to the maintenance of core temperature. However, both alpha- and beta-receptor mechanisms had to be interrupted before a deficit in body temperature was detected.
S Subramanian; R R Vollmer
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Pharmacology, biochemistry, and behavior     Volume:  68     ISSN:  0091-3057     ISO Abbreviation:  Pharmacol. Biochem. Behav.     Publication Date:  2001 Mar 
Date Detail:
Created Date:  2001-04-30     Completed Date:  2001-07-19     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  0367050     Medline TA:  Pharmacol Biochem Behav     Country:  United States    
Other Details:
Languages:  eng     Pagination:  597-602     Citation Subset:  IM    
Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, PA 15261, USA.
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MeSH Terms
Adipose Tissue, Brown / drug effects,  metabolism*
Adrenal Glands / drug effects,  metabolism
Adrenergic alpha-Antagonists / pharmacology*
Adrenergic beta-Antagonists / pharmacology*
Body Temperature / drug effects
Cold Temperature / adverse effects*
Motor Activity / drug effects
Norepinephrine / metabolism*
Phentolamine / pharmacology
Propranolol / pharmacology
Rats, Sprague-Dawley
Grant Support
Reg. No./Substance:
0/Adrenergic alpha-Antagonists; 0/Adrenergic beta-Antagonists; 50-60-2/Phentolamine; 51-41-2/Norepinephrine; 525-66-6/Propranolol

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