NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Valsalva's maneuver revisited: a quantitative method yielding insights into human autonomic controlSeventeen healthy supine subjects performed graded Valsalva maneuvers. In four subjects, transesophageal echographic aortic cross-sectional areas decreased during and increased after straining. During the first seconds of straining, when aortic cross-sectional area was declining and peripheral arterial pressure was rising, peroneal sympathetic muscle neurons were nearly silent. Then, as aortic cross-sectional area and peripheral pressure both declined, sympathetic muscle nerve activity increased, in proportion to the intensity of straining. Poststraining arterial pressure elevations were proportional to preceding increases of sympathetic activity. Sympathetic inhibition after straining persisted much longer than arterial and right atrial pressure elevations. Similarly, R-R intervals changed in parallel with peripheral arterial pressure, until approximately 45 s after the onset of straining, when R-R intervals were greater and arterial pressures were smaller than prestraining levels. Our conclusions are as follows: opposing changes of carotid and aortic baroreceptor inputs reduce sympathetic muscle and increase vagal cardiac motor neuronal firing; parallel changes of barorsensory inputs provoke reciprocal changes of sympathetic and direct changes of vagal firing; and pressure transients lasting only seconds reset arterial pressure-sympathetic and -vagal response relations.
Document ID
20040173155
Document Type
Reprint (Version printed in journal)
Authors
Smith, M. L. (Hunter Holmes McGuire Department of Veterans Affairs Medical Center Richmond, Virginia, United States)
Beightol, L. A.
Fritsch-Yelle, J. M.
Ellenbogen, K. A.
Porter, T. R.
Eckberg, D. L.
Date Acquired
August 22, 2013
Publication Date
September 1, 1996
Publication Information
Publication: The American journal of physiology
Volume: 271
Issue: 3 Pt 2
ISSN: 0002-9513
Subject Category
Aerospace Medicine
Funding Number(s)
CONTRACT_GRANT: HL-22296
CONTRACT_GRANT: HL-30506
CONTRACT_GRANT: HL-07556
Distribution Limits
Public
Copyright
Other
Keywords
NASA Center JSC
Non-NASA Center
NASA Discipline Cardiopulmonary