| Effects of aging and exercise training on spinotrapezius muscle microvascular PO2 dynamics and vasomotor control. | |
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MedLine Citation:
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PMID: 21212242 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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With advancing age, there is a reduction in exercise tolerance, resulting, in part, from a perturbed ability to match O(2) delivery to uptake within skeletal muscle. In the spinotrapezius muscle (which is not recruited during incline treadmill running) of aged rats, we tested the hypotheses that exercise training will 1) improve the matching of O(2) delivery to O(2) uptake, evidenced through improved microvascular Po(2) (Pm(O(2))), at rest and throughout the contractions transient; and 2) enhance endothelium-dependent vasodilation in first-order arterioles. Young (Y, ∼6 mo) and aged (O, >24 mo) Fischer 344 rats were assigned to control sedentary (YSED; n = 16, and OSED; n = 15) or exercise-trained (YET; n = 14, and OET; n = 13) groups. Spinotrapezius blood flow (via radiolabeled microspheres) was measured at rest and during exercise. Phosphorescence quenching was used to quantify Pm(O(2)) in vivo at rest and across the rest-to-twitch contraction (1 Hz, 5 min) transition in the spinotrapezius muscle. In a follow-up study, vasomotor responses to endothelium-dependent (acetylcholine) and -independent (sodium nitroprusside) stimuli were investigated in vitro. Blood flow to the spinotrapezius did not increase above resting values during exercise in either young or aged groups. Exercise training increased the precontraction baseline Pm(O(2)) (OET 37.5 ± 3.9 vs. OSED 24.7 ± 3.6 Torr, P < 0.05); the end-contracting Pm(O(2)) and the time-delay before Pm(O(2)) fell in the aged group but did not affect these values in the young. Exercise training improved maximal vasodilation in aged rats to acetylcholine (OET 62 ± 16 vs. OSED 27 ± 16%) and to sodium nitroprusside in both young and aged rats. Endurance training of aged rats enhances the Pm(O(2)) in a nonrecruited skeletal muscle and is associated with improved vascular smooth muscle function. These data support the notion that improvements in vascular function with exercise training are not isolated to the recruited muscle. |
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Authors:
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Danielle J McCullough; Robert T Davis; James M Dominguez; John N Stabley; Christian S Bruells; Bradley J Behnke |
Publication Detail:
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Type: Journal Article; Research Support, N.I.H., Extramural Date: 2011-01-06 |
Journal Detail:
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Title: Journal of applied physiology (Bethesda, Md. : 1985) Volume: 110 ISSN: 1522-1601 ISO Abbreviation: J. Appl. Physiol. Publication Date: 2011 Mar |
Date Detail:
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Created Date: 2011-03-09 Completed Date: 2011-07-07 Revised Date: 2012-03-01 |
Medline Journal Info:
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Nlm Unique ID: 8502536 Medline TA: J Appl Physiol Country: United States |
Other Details:
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Languages: eng Pagination: 695-704 Citation Subset: IM |
Affiliation:
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Dept. of Applied Physiology & Kinesiology, Univ. of Florida, Gainesville, FL 32611, USA. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Aging
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physiology* Animals Feedback, Physiological / physiology Male Muscle, Skeletal / blood supply, physiology* Oxygen / metabolism* Oxygen Consumption / physiology* Physical Conditioning, Animal / methods* Physical Exertion / physiology* Rats Rats, Inbred F344 Vasomotor System / physiology* |
| Grant Support | |
ID/Acronym/Agency:
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K01-AG032327/AG/NIA NIH HHS; R36 AG036816-02/AG/NIA NIH HHS; R36-AG036816/AG/NIA NIH HHS |
| Chemical | |
Reg. No./Substance:
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7782-44-7/Oxygen |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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