NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Attenuated baroreflex control of sympathetic nerve activity after cardiovascular deconditioning in ratsThe effect of cardiovascular deconditioning on baroreflex control of the sympathetic nervous system was evaluated after 14 days of hindlimb unloading (HU) or the control condition. Rats were chronically instrumented with catheters and sympathetic nerve recording electrodes for measurement of mean arterial pressure (MAP) and heart rate (HR) and recording of lumbar (LSNA) or renal (RSNA) sympathetic nerve activity. Experiments were conducted 24 h after surgery, with the animals in a normal posture. Baroreflex function was assessed using a logistic function that related HR and LSNA or RSNA to MAP during infusion of phenylephrine and nitroprusside. Baroreflex influence on HR was not affected by HU. Maximum baroreflex-elicited LSNA was significantly reduced in HU rats (204 +/- 11.9 vs. 342 +/- 30.6% baseline LSNA), as was maximum reflex gain (-4.0 +/- 0.6 vs. -7.8 +/- 1.3 %LSNA/mmHg). Maximum baroreflex-elicited RSNA (259 +/- 10.8 vs. 453 +/- 28.0% baseline RSNA), minimum baroreflex-elicited RSNA (-2 +/- 2.8 vs. 13 +/- 4.5% baseline RSNA), and maximum gain (-5.8 +/- 0.5 vs. -13.6 +/- 3.1 %RSNA/mmHg) were significantly decreased in HU rats. Results demonstrate that baroreflex modulation of sympathetic nervous system activity is attenuated after cardiovascular deconditioning in rodents. Data suggest that alterations in the arterial baroreflex may contribute to orthostatic intolerance after a period of bedrest or spaceflight in humans.
Document ID
20040172678
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Moffitt, J. A.
(Dalton Cardiovascular Research Center, University of Missouri Columbia 65211, United States)
Foley, C. M.
Schadt, J. C.
Laughlin, M. H.
Hasser, E. M.
Date Acquired
August 22, 2013
Publication Date
May 1, 1998
Publication Information
Publication: The American journal of physiology
Volume: 274
Issue: 5 Pt 2
ISSN: 0002-9513
Subject Category
Life Sciences (General)
Funding Number(s)
CONTRACT_GRANT: HL-55306
Distribution Limits
Public
Copyright
Other
Keywords
NASA Discipline Cardiopulmonary
Non-NASA Center

Available Downloads

There are no available downloads for this record.
No Preview Available