Document Detail

Norepinephrine spillover from skeletal muscle during exercise in humans: role of muscle mass.
MedLine Citation:
PMID:  2603969     Owner:  NLM     Status:  MEDLINE    
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.
G K Savard; E A Richter; S Strange; B Kiens; N J Christensen; B Saltin
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The American journal of physiology     Volume:  257     ISSN:  0002-9513     ISO Abbreviation:  Am. J. Physiol.     Publication Date:  1989 Dec 
Date Detail:
Created Date:  1990-02-02     Completed Date:  1990-02-02     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  0370511     Medline TA:  Am J Physiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  H1812-8     Citation Subset:  IM; S    
August Krogh Institute, University of Copenhagen, Denmark.
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MeSH Terms
Arm / blood supply
Blood Pressure
Cardiac Output
Epinephrine / blood
Heart Rate
Leg / blood supply
Muscles / anatomy & histology,  blood supply,  physiology*
Norepinephrine / blood,  metabolism*
Oxygen / blood
Oxygen Consumption
Physical Exertion*
Reference Values
Regional Blood Flow
Reg. No./Substance:
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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