| Influences of chemical sympathectomy and simulated weightlessness on male and female rats. | |
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MedLine Citation:
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PMID: 1757295 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Maximum oxygen consumption (VO2max) has been shown to be reduced after periods of simulated weightlessness. To assess the role of the sympathetic nervous system in these reductions, Sprague-Dawley rats were either chemically sympathectomized (SYMX) or injected with saline (SHAM) and assigned to head-down suspension (HDS), horizontal restraint with the hindlimbs weight bearing (HWB), or cage-control (CC) conditions. VO2max, run time (RT), and mechanical efficiency (ME) were measured before suspension and on days 7 and 14. Male and female SHAM HDS groups exhibited reduced measures of VO2max (12-13%) after 7 and 14 days, and this decrease was attenuated in the SYMX and HWB rats. HDS resulted in a significant reduction in RT (9-15%) in both the male and female rats, and ME was significantly reduced after HDS in male and female SYMX and male SHAM rats (23-33%) but not in the female SHAM rats. Lesser reductions in ME were observed in the HWB rats. HDS and HWB were associated with lower body, fat-free, and fat masses, which were similar in male and female rats as well as for the SHAM and SYMX conditions. In a related HDS experiment with normal rats, plasma norepinephrine and epinephrine were increased by 53 and 42% after 7 days, but only epinephrine returned to baseline after 14 days. It was concluded that chemical sympathectomy and/or a weight-bearing stimulus will attenuate the loss in VO2max associated with simulated weightlessness in rats despite similar changes in body mass and composition. The mechanism(s) remains unclear at this time. |
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Authors:
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C R Woodman; C S Stump; J A Stump; L A Sebastian; Z Rahman; C M Tipton |
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Publication Detail:
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Type: Comparative Study; Journal Article; Research Support, U.S. Gov't, Non-P.H.S. |
Journal Detail:
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Title: Journal of applied physiology (Bethesda, Md. : 1985) Volume: 71 ISSN: 8750-7587 ISO Abbreviation: J. Appl. Physiol. Publication Date: 1991 Sep |
Date Detail:
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Created Date: 1992-01-31 Completed Date: 1992-01-31 Revised Date: 2008-11-21 |
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: 1005-14 Citation Subset: IM; S |
Affiliation:
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Department of Exercise and Sport Sciences, School of Health Related Professions, University of Arizona, Tucson 85721. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Adrenal Glands
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physiology Animals Body Composition / physiology Body Weight / physiology Catecholamines / blood Drinking / physiology Eating / physiology Female Guanethidine / pharmacology Heart / physiology Male Muscles / physiology Organ Size / physiology Oxygen Consumption / physiology Physical Exertion / physiology Rats Rats, Inbred Strains Restraint, Physical Sex Factors Sympathectomy, Chemical Sympathetic Nervous System / physiology* Weightlessness / adverse effects* |
| Chemical | |
Reg. No./Substance:
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0/Catecholamines; 55-65-2/Guanethidine |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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