Document Detail


Effect of exercise training on nitric oxide and superoxide/H₂O₂ signaling pathways in collateral-dependent porcine coronary arterioles.
MedLine Citation:
PMID:  22323648     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Endothelial nitric oxide (NO) synthase (NOS) has been shown to contribute to enhanced vascular function after exercise training. Recent studies have revealed that relatively low concentrations of reactive oxygen species can contribute to endothelium-dependent vasodilation under physiological conditions. We tested the hypothesis that exercise training enhances endothelial function via endothelium-derived vasodilators, NO and superoxide/H(2)O(2), in the underlying setting of chronic coronary artery occlusion. An ameroid constrictor was placed around the proximal left circumflex coronary artery to induce gradual occlusion in Yucatan miniature swine. At 8 wk postoperatively, pigs were randomly assigned to sedentary (pen-confined) or exercise-training (treadmill-run: 5 days/wk for 14 wk) regimens. Exercise training significantly enhanced concentration-dependent, bradykinin-mediated dilation in cannulated collateral-dependent arterioles (∼130 μm diameter) compared with sedentary pigs. NOS inhibition reversed training-enhanced dilation at low bradykinin concentrations in collateral-dependent arterioles, although increased dilation persisted at higher bradykinin concentrations. Total and phosphorylated (Ser(1179)) endothelial NOS protein levels were significantly increased in arterioles from collateral-dependent compared with the nonoccluded region, independent of exercise. The H(2)O(2) scavenger polyethylene glycol-catalase abolished the training-enhanced bradykinin-mediated dilation in collateral-dependent arterioles; similar results were observed with the SOD inhibitor diethyldithiocarbamate. Fluorescence measures of bradykinin-stimulated H(2)O(2) levels were significantly increased by exercise training, independent of occlusion. The NADPH inhibitor apocynin significantly attenuated bradykinin-mediated dilation in arterioles of exercise-trained, but not sedentary, pigs and was associated with significantly increased protein levels of the NADPH subunit p67phox. These data provide evidence that, in addition to NO, the superoxide/H(2)O(2) signaling pathway significantly contributes to exercise training-enhanced endothelium-mediated dilation in collateral-dependent coronary arterioles.
Authors:
Wei Xie; Janet L Parker; Cristine L Heaps
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural     Date:  2012-02-09
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  112     ISSN:  1522-1601     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  2012 May 
Date Detail:
Created Date:  2012-05-02     Completed Date:  2012-08-27     Revised Date:  2013-05-20    
Medline Journal Info:
Nlm Unique ID:  8502536     Medline TA:  J Appl Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1546-55     Citation Subset:  IM    
Affiliation:
Department of Veterinary Physiology and Pharmacology, Texas A & M University, College Station, TX 77843, USA.
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MeSH Terms
Descriptor/Qualifier:
Animals
Arterioles / metabolism,  physiopathology
Collateral Circulation* / drug effects
Coronary Circulation* / drug effects
Coronary Occlusion / metabolism*,  physiopathology
Coronary Vessels / drug effects,  metabolism*,  physiopathology
Disease Models, Animal
Dose-Response Relationship, Drug
Endothelium, Vascular / metabolism,  physiopathology
Enzyme Inhibitors / pharmacology
Female
Free Radical Scavengers / pharmacology
Hydrogen Peroxide / metabolism*
Microscopy, Fluorescence
Microscopy, Video
Muscle, Smooth, Vascular / metabolism,  physiopathology
NADPH Oxidase / antagonists & inhibitors,  metabolism
Nitric Oxide / metabolism*
Nitric Oxide Synthase Type III / antagonists & inhibitors,  metabolism
Phosphorylation
Physical Exertion*
Signal Transduction* / drug effects
Superoxides / metabolism*
Swine
Swine, Miniature
Time Factors
Vasodilation
Vasodilator Agents / pharmacology
Grant Support
ID/Acronym/Agency:
R01-GM-046441/GM/NIGMS NIH HHS; R01-HL-064931/HL/NHLBI NIH HHS
Chemical
Reg. No./Substance:
0/Enzyme Inhibitors; 0/Free Radical Scavengers; 0/Vasodilator Agents; 10102-43-9/Nitric Oxide; 11062-77-4/Superoxides; 7722-84-1/Hydrogen Peroxide; EC 1.14.13.39/Nitric Oxide Synthase Type III; EC 1.6.3.1/NADPH Oxidase
Comments/Corrections

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


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