| Absence of excess peripheral muscle fatigue during beta-adrenoceptor blockade. | |
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MedLine Citation:
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PMID: 2898255 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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1. In eight normal volunteers, the adductor pollicis (AP) was fatigued using intermittent trains of programmed, supramaximal stimulation at 1, 10, 20, 50, 100 and 1 Hz. Activity protocols were performed both with and without circulatory occlusion, both without and during propranolol 80 mg thrice daily in order to investigate the effects of beta-adrenoceptor blockade on 'peripheral' fatigue mechanisms. 2. The degree of beta-adrenoceptor blockade was assessed by the reduction of exercise tachycardia during cycle ergometry, e.g. pulse rates at 210 watts were reduced from 190 +/- 15 to 127 +/- 5 beats min-1 (mean +/- 1 s.d.) indicating that beta-adrenoceptor blockade was substantial and highly significant (P less than 0.001). 3. Before, during and following fatiguing activity with circulatory occlusion force declines were identical during and without beta-adrenoceptor blockade. During and following activity without occlusion, there were slight declines in force which were questionably significantly different at 20 Hz (P less than 0.05). 4. The compound muscle action potential (CMAP) amplitude, measured from the skin surface over the muscle, was unaltered by beta-adrenoceptor blockade before, during or after activity whether with or without circulatory occlusion. 5. The maximal relaxation rate (MRR) was not significantly reduced in previously unfatigued muscle during beta-adrenoceptor blockade. During activity, both with and without circulatory occlusion, there was no evidence that MRR was reduced significantly more during beta-adrenoceptor blockade. 6. The absence of a convincing effect of beta-adrenoceptor blockade on peripheral fatigue mechanisms may indicate that central mechanisms are involved or that impairments of peripheral force production, of a specific nature or as a result of exacerbation of limitations of circulatory oxygen transport, though small are detected during voluntary exercise and give rise to increases in motor unit recruitment and/or firing rates, and hence increased perception of fatigue. |
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Authors:
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R G Cooper; M J Stokes; R H Edwards; R D Stark |
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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: British journal of clinical pharmacology Volume: 25 ISSN: 0306-5251 ISO Abbreviation: Br J Clin Pharmacol Publication Date: 1988 Apr |
Date Detail:
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Created Date: 1988-07-29 Completed Date: 1988-07-29 Revised Date: 2010-09-09 |
Medline Journal Info:
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Nlm Unique ID: 7503323 Medline TA: Br J Clin Pharmacol Country: ENGLAND |
Other Details:
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Languages: eng Pagination: 405-15 Citation Subset: IM; S |
Affiliation:
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Department of Medicine, University of Liverpool. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Adrenergic beta-Antagonists
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pharmacology* Adult Arteries / physiology Blood Pressure / drug effects Electromyography Female Heart Rate / drug effects Humans Male Muscle Contraction / drug effects Muscles / blood supply, drug effects*, physiology Physical Exertion Propranolol / blood, pharmacology Regional Blood Flow / drug effects |
| Chemical | |
Reg. No./Substance:
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0/Adrenergic beta-Antagonists; 525-66-6/Propranolol |
| Comments/Corrections | |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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