| Norepinephrine spillover from skeletal muscle during exercise in humans: role of muscle mass. | |
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MedLine Citation:
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PMID: 2603969 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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The purpose of this study was to determine the effect of increasing muscle mass involvement in dynamic exercise on both sympathetic nervous activation and local hemodynamic variables of individual active and inactive skeletal muscle groups. Six male subjects performed 15-min bouts of one-legged knee extension either alone or in combination with the knee extensors of the other leg and/or with the arms. The range of work intensities varied between 24 and 71% (mean) of subjects' maximal aerobic capacity (% VO2max). Leg blood flow, measured in the femoral vein by thermodilution, was determined in both legs. Arterial and venous plasma concentrations of norepinephrine (NE) and epinephrine were analyzed, and the calculated NE spillover was used as an index of sympathetic nervous activity to the limb. NE spillover increased gradually both in the resting, and to a larger extent in the exercising legs, with a steeper rise occurring approximately 70% VO2max. These increases were not associated with any significant changes in leg blood flow or leg vascular conductance at the exercise intensities examined. These results suggest that, as the total active muscle mass increases, the rise in sympathetic nervous activity to skeletal muscle, either resting or working at a constant load, is not associated with any significant neurogenic vasoconstriction and reduction in flow or conductance through the muscle vascular bed, during whole body exercise demanding up to 71% VO2max. |
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Authors:
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G K Savard; E A Richter; S Strange; B Kiens; N J Christensen; B Saltin |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: The American journal of physiology Volume: 257 ISSN: 0002-9513 ISO Abbreviation: Am. J. Physiol. Publication Date: 1989 Dec |
Date Detail:
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Created Date: 1990-02-02 Completed Date: 1990-02-02 Revised Date: 2008-11-21 |
Medline Journal Info:
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Nlm Unique ID: 0370511 Medline TA: Am J Physiol Country: UNITED STATES |
Other Details:
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Languages: eng Pagination: H1812-8 Citation Subset: IM; S |
Affiliation:
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August Krogh Institute, University of Copenhagen, Denmark. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Adult Arm / blood supply Blood Pressure Cardiac Output Epinephrine / blood Heart Rate Humans Leg / blood supply Male Muscles / anatomy & histology, blood supply, physiology* Norepinephrine / blood, metabolism* Oxygen / blood Oxygen Consumption Physical Exertion* Reference Values Regional Blood Flow |
| Chemical | |
Reg. No./Substance:
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51-41-2/Norepinephrine; 51-43-4/Epinephrine; 7782-44-7/Oxygen |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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