Arterial baroreflex buffering of sympathetic activation during exercise-induced elevations in arterial pressure

Details

Serval ID
serval:BIB_06C53905B7F8
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Arterial baroreflex buffering of sympathetic activation during exercise-induced elevations in arterial pressure
Journal
Journal of Clinical Investigation
Author(s)
Scherrer  U., Pryor  S. L., Bertocci  L. A., Victor  R. G.
ISSN
0021-9738 (Print)
Publication state
Published
Issued date
12/1990
Volume
86
Number
6
Pages
1855-61
Notes
Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, P.H.S. --- Old month value: Dec
Abstract
Static muscle contraction activates metabolically sensitive muscle afferents that reflexively increase sympathetic nerve activity and arterial pressure. To determine if this contraction-induced reflex is modulated by the sinoaortic baroreflex, we performed microelectrode recordings of sympathetic nerve activity to resting leg muscle during static handgrip in humans while attempting to clamp the level of baroreflex stimulation by controlling the exercise-induced rise in blood pressure with pharmacologic agents. The principal new finding is that partial pharmacologic suppression of the rise in blood pressure during static handgrip (nitroprusside infusion) augmented the exercise-induced increases in heart rate and sympathetic activity by greater than 300%. Pharmacologic accentuation of the exercise-induced rise in blood pressure (phenylephrine infusion) attenuated these reflex increases by greater than 50%. In contrast, these pharmacologic manipulations in arterial pressure had little or no effect on: (a) forearm muscle cell pH, an index of the metabolic stimulus to skeletal muscle afferents; or (b) central venous pressure, an index of the mechanical stimulus to cardiopulmonary afferents. We conclude that in humans the sinoaortic baroreflex is much more effective than previously thought in buffering the reflex sympathetic activation caused by static muscle contraction.
Keywords
Adult Blood Pressure *Exertion Heart Rate Humans Hydrogen-Ion Concentration Male Muscles/physiology Nitroprusside/pharmacology Phenylephrine/pharmacology Pressoreceptors/*physiology Reflex/physiology Sympathetic Nervous System/*physiology
Pubmed
Web of science
Open Access
Yes
Create date
25/01/2008 14:04
Last modification date
20/08/2019 12:29
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