| Impact of dietary nitrate supplementation via beetroot juice on exercising muscle vascular control in rats. | |
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MedLine Citation:
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PMID: 23070702 Owner: NLM Status: Publisher |
Abstract/OtherAbstract:
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Dietary nitrate (NO(3)(-)) supplementation, via its reduction to nitrite (NO(2)(-)) and subsequent conversion to nitric oxide (NO), 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 BR; 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 (measured via radiolabeled 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 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 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 percent type IIb + d/x muscle fibers (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. |
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Authors:
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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:
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Type: JOURNAL ARTICLE Date: 2012-10-15 |
Journal Detail:
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Title: The Journal of physiology Volume: - ISSN: 1469-7793 ISO Abbreviation: J. Physiol. (Lond.) Publication Date: 2012 Oct |
Date Detail:
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Created Date: 2012-10-16 Completed Date: - Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 0266262 Medline TA: J Physiol Country: - |
Other Details:
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Languages: ENG Pagination: - Citation Subset: - |
Affiliation:
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Kansas State University; |
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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