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    
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.
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    
Division of Geriatrics, Department of Internal Medicine, University of Utah, Salt Lake City, Utah 84148, USA.
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MeSH Terms
Brachial Artery / physiology,  ultrasonography
Exercise / physiology*
Hand / blood supply*,  physiology*,  ultrasonography
Hand Strength / physiology*
Hemodynamics / drug effects,  physiology
Hyperemia / physiopathology
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
Reg. No./Substance:
0/Vasodilator Agents; 10102-43-9/Nitric Oxide; 17035-90-4/omega-N-Methylarginine; EC Oxide Synthase

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