Document Detail

Impact of dietary nitrate supplementation via beetroot juice on exercising muscle vascular control in rats.
MedLine Citation:
PMID:  23070702     Owner:  NLM     Status:  MEDLINE    
Dietary nitrate (NO(3)(-)) supplementation, via its reduction to nitrite (NO(2)(-)) and subsequent conversion to nitric oxide (NO) and other reactive nitrogen intermediates, reduces blood pressure and the O(2) cost of submaximal exercise in humans. Despite these observations, the effects of dietary NO(3)(-) supplementation on skeletal muscle vascular control during locomotory exercise remain unknown. We tested the hypotheses that dietary NO(3)(-) supplementation via beetroot juice (BR) would reduce mean arterial pressure (MAP) and increase hindlimb muscle blood flow in the exercising rat. Male Sprague-Dawley rats (3-6 months) were administered either NO(3)(-) (via beetroot juice; 1 mmol kg(-1) day(-1), BR n = 8) or untreated (control, n = 11) tap water for 5 days. MAP and hindlimb skeletal muscle blood flow and vascular conductance (radiolabelled microsphere infusions) were measured during submaximal treadmill running (20 m min(-1), 5% grade). BR resulted in significantly lower exercising MAP (control: 137 ± 3, BR: 127 ± 4 mmHg, P < 0.05) and blood [lactate] (control: 2.6 ± 0.3, BR: 1.9 ± 0.2 mm, P < 0.05) compared to control. Total exercising hindlimb skeletal muscle blood flow (control: 108 ± 8, BR: 150 ± 11 ml min(-1) (100 g)(-1), P < 0.05) and vascular conductance (control: 0.78 ± 0.05, BR: 1.16 ± 0.10 ml min(-1) (100 g)(-1) mmHg(-1), P < 0.05) were greater in rats that received BR compared to control. The relative differences in blood flow and vascular conductance for the 28 individual hindlimb muscles and muscle parts correlated positively with their percentage type IIb + d/x muscle fibres (blood flow: r = 0.74, vascular conductance: r = 0.71, P < 0.01 for both). These data support the hypothesis that NO(3)(-) supplementation improves vascular control and elevates skeletal muscle O(2) delivery during exercise predominantly in fast-twitch type II muscles, and provide a potential mechanism by which NO(3)(-) supplementation improves metabolic control.
Scott K Ferguson; Daniel M Hirai; Steven W Copp; Clark T Holdsworth; Jason D Allen; Andrew M Jones; Timothy I Musch; David C Poole
Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't     Date:  2012-10-15
Journal Detail:
Title:  The Journal of physiology     Volume:  591     ISSN:  1469-7793     ISO Abbreviation:  J. Physiol. (Lond.)     Publication Date:  2013 Jan 
Date Detail:
Created Date:  2013-01-16     Completed Date:  2013-06-21     Revised Date:  2014-01-24    
Medline Journal Info:
Nlm Unique ID:  0266262     Medline TA:  J Physiol     Country:  England    
Other Details:
Languages:  eng     Pagination:  547-57     Citation Subset:  IM    
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MeSH Terms
Beta vulgaris / chemistry
Blood Pressure / drug effects
Dietary Supplements
Hindlimb / blood supply
Motor Activity*
Muscle, Skeletal / blood supply,  physiology*
Nitrates / blood,  pharmacology*
Nitrites / blood
Oxygen Consumption / drug effects
Rats, Sprague-Dawley
Regional Blood Flow / drug effects*
Grant Support
Reg. No./Substance:
0/Nitrates; 0/Nitrites

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

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