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Cardiovascular and hormonal (aldosterone) responses in a rat model which mimics responses to weightlessnessCardiovascular responses and fluid/electrolyte shifts seen during spaceflight have been attributed to cephalad redistribution of vascular fluid. The antiorthostatic (AO) rat (suspended, head-down tilt of 15-20 deg) is used to model these responses. This study documents that elevated blood pressures in AO rats are sustained for periods of up to seven days, compared with presuspension values. Increased blood pressures in AO rats suggests a specific response to AO positioning, potentially relatable to a cephalad fluid shift. To assess a role for hormonal regulation of sodium excretion, serum aldosterone levels were measured. Circulating aldosterone concentrations were seen to increase approximately 100 percent during seven days of AO suspension, concurrently with a pronounced natriuresis. These results suggest that aldosterone may not be involved in the long term regulation of increased Na(+) excretion in AO animals. These studies continue to show the usefulness of models for the development of animal protocols for space flight.
Document ID
19850065038
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Musacchia, X. J.
(Louisville Univ. KY, United States)
Steffen, J. M.
(Louisville, University KY, United States)
Date Acquired
August 12, 2013
Publication Date
December 1, 1984
Publication Information
Publication: Physiologist, Supplement
Volume: 27
ISSN: 0031-9376
Subject Category
Life Sciences (General)
Accession Number
85A47189
Funding Number(s)
CONTRACT_GRANT: NSG-2325
Distribution Limits
Public
Copyright
Other

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