Document Detail


Progressive handgrip exercise: evidence of nitric oxide-dependent vasodilation and blood flow regulation in humans.
MedLine Citation:
PMID:  21217074     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
In the peripheral circulation, nitric oxide (NO) is released in response to shear stress across vascular endothelial cells. We sought to assess the degree to which NO contributes to exercise-induced vasodilation in the brachial artery (BA) and to determine the potential of this approach to noninvasively evaluate NO bioavailability. In eight young (25 ± 1 yr) healthy volunteers, we used ultrasound Doppler to examine BA vasodilation in response to handgrip exercise (4, 8, 12, 16, 20, and 24 kg) with and without endothelial NO synthase blockade [intra-arterial N(G)-monomethyl-L-arginine (L-NMMA), 0.48 mg · dl(-1) · min(-1)]. Higher exercise intensities evoked significant BA vasodilation (4-12%) that was positively correlated with the hyperemic stimulus (r = 0.98 ± 0.003, slope = 0.005 ± 0.001). During NO blockade, BA vasodilation at the highest exercise intensity was reduced by ∼70% despite similar exercise-induced increases in shear rate (control, +224 ± 30 s(-1); L-NMMA, +259 ± 46 s(-1)). The relationship and slope of BA vasodilation with increasing shear rate was likewise reduced (r = 0.48 ± 0.1, slope = 0.0007 ± 0.0005). We conclude that endothelial NO synthase inhibition with L-NMMA abolishes the relationship between shear stress and BA vasodilation during handgrip exercise, providing clear evidence of NO-dependent vasodilation in this experimental model. These results support this paradigm as a novel and valid approach for a noninvasive assessment of NO-dependent vasodilation in humans.
Authors:
D Walter Wray; Melissa A H Witman; Stephen J Ives; John McDaniel; Anette S Fjeldstad; Joel D Trinity; Jamie D Conklin; Mark A Supiano; Russell S Richardson
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.     Date:  2011-01-07
Journal Detail:
Title:  American journal of physiology. Heart and circulatory physiology     Volume:  300     ISSN:  1522-1539     ISO Abbreviation:  Am. J. Physiol. Heart Circ. Physiol.     Publication Date:  2011 Mar 
Date Detail:
Created Date:  2011-03-03     Completed Date:  2011-05-26     Revised Date:  2013-07-03    
Medline Journal Info:
Nlm Unique ID:  100901228     Medline TA:  Am J Physiol Heart Circ Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  H1101-7     Citation Subset:  IM    
Affiliation:
Division of Geriatrics, Department of Internal Medicine, University of Utah, Salt Lake City, Utah 84148, USA. walter.wray@hsc.utah.edu
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MeSH Terms
Descriptor/Qualifier:
Adult
Brachial Artery / physiology,  ultrasonography
Exercise / physiology*
Female
Hand / blood supply*,  physiology*,  ultrasonography
Hand Strength / physiology*
Hemodynamics / drug effects,  physiology
Humans
Hyperemia / physiopathology
Male
Nitric Oxide / physiology*
Nitric Oxide Synthase / antagonists & inhibitors
Regional Blood Flow / drug effects,  physiology
Vasodilation / physiology*
Vasodilator Agents / metabolism
Young Adult
omega-N-Methylarginine / physiology
Grant Support
ID/Acronym/Agency:
AG-028403/AG/NIA NIH HHS; P01-HL-091830/HL/NHLBI NIH HHS
Chemical
Reg. No./Substance:
0/Vasodilator Agents; 10102-43-9/Nitric Oxide; 17035-90-4/omega-N-Methylarginine; EC 1.14.13.39/Nitric Oxide Synthase
Comments/Corrections

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