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Effects of Aging, TNF-α and Exercise Training On Angiotensin II-Induced Vasoconstriction of Rat Skeletal Muscle Arterioles.
MedLine Citation:
PMID:  22923503     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
Skeletal muscle vascular resistance during physical exertion is higher with old age. The purpose of this study was to determine whether, 1) aging enhances angiotensin II (ANG II)-induced vasoconstriction, 2) the pro-inflammatory cytokine tumor necrosis factor alpha (TNF-α) contributes to alterations in ANG II-mediated vasoconstriction with aging, 3) exercise training attenuates putative age-associated increases in ANG II-mediated vasoconstriction, and 4) the mechanism(s) through which aging and exercise training alter ANG II-induced vasoconstriction in skeletal muscle arterioles. Male Fischer 344 rats were assigned to 4 groups: young sedentary (YS; 4 months), old sedentary (OS; 24 months), young trained (YT) and old trained (OT). In a separate group of YS and OS animals, a TNF type 1 receptor (TNF-R1) inhibitor was administered subcutaneously for 10 wk. First-order arterioles were isolated from soleus and gastrocnemius muscles for in vitro experimentation. Old age augmented ANG II-induced vasoconstriction in both soleus (young: 27 ± 3%; old: 38 ± 4%) and gastrocnemius (young: 42 ± 6%; old: 64 ± 9%) muscle arterioles; this augmented vasoconstriction was abolished with the removal of the endothelium, NPPGPP-nitro-L-arginine methyl ester (L-NAME), and chronic inhibition of TNF-α. In addition, exercise training ameliorated the age-induced increase in ANG II-vasoconstriction. These findings demonstrate that old age enhances and exercise training diminishes ANG II-induced vasoconstrictor responses in skeletal muscle arterioles through an endothelium-dependent NOS signaling pathway. In addition, the enhancement of ANG II vasoconstriction with old age appears to be related to a proinflammatory state.
Authors:
Yoonjung Park; Rhonda D Prisby; Bradley Jon Behnke; James Michael Dominguez; Lisa A Lesniewski; Anthony John Donato; Judy M Muller-Delp; Micheal D Delp
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Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2012-8-23
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  -     ISSN:  1522-1601     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  2012 Aug 
Date Detail:
Created Date:  2012-8-27     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8502536     Medline TA:  J Appl Physiol     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Affiliation:
1Texas Tech University.
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