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postural regulation of muscle sympathetic nerve activity before and after simulated and actual microgravity deconditioningThe etiology of orthostatic intolerance after spaceflight is multifaceted. Morphological adaptations, in particular cardiac atrophy, are likely to magnify the decrease in stroke volume that occurs with reductions in cardiac filling pressure when standing. Neural adaptations may be inferred as well, as reductions in carotid-cardiac baroreflex responsiveness have been reported following bedrest deconditioning and spaceflight. Neural control of vascular resistance has not been studied directly when orthostatic intolerance is florid in the hours following spaceflight. However, the increases in systemic vascular resistance and plasma catecholamines during orthostatic stress are inappropriately low in orthostatically intolerant subjects following spaceflight, suggesting that deficits in the regulation of vascular resistance may be associated with hypoadrenergic function. The studies described in this abstract were designed to test this hypothesis.
Document ID
20000020559
Document Type
Conference Paper
Authors
Pawelczyk, J. A.
(Pennsylvania State Univ. University Park, PA United States)
Levine, B. D.
(Presbyterian Hospital of Dallas Dallas, TX United States)
Date Acquired
August 19, 2013
Publication Date
January 1, 1999
Publication Information
Publication: Proceedings of the First Biennial Space Biomedical Investigators' Workshop
Subject Category
Aerospace Medicine
Funding Number(s)
CONTRACT_GRANT: NAGW-3582
CONTRACT_GRANT: NAS9-19429
CONTRACT_GRANT: NAS9-19573
CONTRACT_GRANT: NAGW-4389
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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IDRelationTitle20000020485Analytic PrimaryProceedings of the First Biennial Space Biomedical Investigators' Workshop
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