| Altered mechanisms of sympathetic activation during rhythmic forearm exercise in heart failure. | |
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MedLine Citation:
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PMID: 9572798 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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In congestive heart failure (CHF), the mechanisms of exercise-induced sympathoexcitation are poorly defined. We compared the responses of sympathetic nerve activity directed to muscle (MSNA) and to skin (SSNA, peroneal microneurography) during rhythmic handgrip (RHG) at 25% of maximal voluntary contraction and during posthandgrip circulatory arrest (PHG-CA) in CHF patients with those of an age-matched control group. During RHG, the CHF patients fatigued prematurely. At end exercise, the increase in MSNA was similar in both groups (CHF patients, n = 12; controls, n = 10). However, during PHG-CA, in the controls MSNA returned to baseline, whereas it remained elevated in CHF patients (P < 0.05). Similarly, at end exercise, the increase in SSNA was comparable in both groups (CHF patients, n = 11; controls, n = 12), whereas SSNA remained elevated during PHG-CA in CHF patients but not in the controls (P < 0.05). In a separate control group (n = 6), even high-intensity static handgrip was not accompanied by sustained elevation of SSNA during PHG-CA. 31P-nuclear magnetic resonance spectroscopy during RHG demonstrated significant muscle acidosis and accumulation of inorganic phosphate in CHF patients (n = 7) but not in controls (n = 9). We conclude that in CHF patients rhythmic forearm exercise leads to premature fatigue and accumulation of muscle metabolites. The prominent PHG-CA response of MSNA and SSNA in CHF patients suggests activation of the muscle metaboreflex. Because, in contrast to controls, in CHF patients both MSNA and SSNA appear to be under muscle metaboreflex control, the mechanisms and distribution of sympathetic outflow during exercise appear to be different from normal. |
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Authors:
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D H Silber; G Sutliff; Q X Yang; M B Smith; L I Sinoway; U A Leuenberger |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.; Research Support, U.S. Gov't, P.H.S. |
Journal Detail:
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Title: Journal of applied physiology (Bethesda, Md. : 1985) Volume: 84 ISSN: 8750-7587 ISO Abbreviation: J. Appl. Physiol. Publication Date: 1998 May |
Date Detail:
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Created Date: 1998-06-04 Completed Date: 1998-06-04 Revised Date: 2007-11-15 |
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: 1551-9 Citation Subset: IM; S |
Affiliation:
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Department of Medicine, The Milton S. Hershey Medical Center, 17033, Pennsylvania, USA. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Adult Aged Blood Pressure / physiology Exercise / physiology* Forearm / physiology* Heart Failure / physiopathology* Heart Rate / physiology Humans Magnetic Resonance Spectroscopy Male Middle Aged Muscle Contraction / physiology Skin / metabolism Sympathetic Nervous System / physiology* |
| Grant Support | |
ID/Acronym/Agency:
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AG-12227/AG/NIA NIH HHS; HL-02654/HL/NHLBI NIH HHS |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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