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Vestibular control of sympathetic activity. An otolith-sympathetic reflex in humansIt has been proposed that a vestibular reflex originating in the otolith organs and other body graviceptors modulates sympathetic activity during changes in posture with regard to gravity. To test this hypothesis, we selectively stimulated otolith and body graviceptors sinusoidally along different head axes in the coronal plane with off-vertical axis rotation (OVAR) and recorded sympathetic efferent activity in the peroneal nerve (muscle sympathetic nerve activity, MSNA), blood pressure, heart rate, and respiratory rate. All parameters were entrained during OVAR at the frequency of rotation, with MSNA increasing in nose-up positions during forward linear acceleration and decreasing when nose-down. MSNA was correlated closely with blood pressure when subjects were within +/-90 degrees of nose-down positions with a delay of 1.4 s, the normal latency of baroreflex-driven changes in MSNA. Thus, in the nose-down position, MSNA was probably driven by baroreflex afferents. In contrast, when subjects were within +/-45 degrees of the nose-up position, i.e., when positive linear acceleration was maximal along the naso-ocipital axis, MSNA was closely related to gravitational acceleration at a latency of 0.4 s. This delay is too short for MSNA changes to be mediated by the baroreflex, but it is compatible with the delay of a response originating in the vestibular system. We postulate that a vestibulosympathetic reflex, probably originating mainly in the otolith organs, contributes to blood pressure maintenance during forward linear acceleration. Because of its short latency, this reflex may be one of the earliest mechanisms to sustain blood pressure upon standing.
Document ID
20040088398
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Kaufmann, H.
(Mount Sinai School of Medicine New York, NY 10029, United States)
Biaggioni, I.
Voustianiouk, A.
Diedrich, A.
Costa, F.
Clarke, R.
Gizzi, M.
Raphan, T.
Cohen, B.
Date Acquired
August 21, 2013
Publication Date
April 1, 2002
Publication Information
Publication: Experimental brain research. Experimentelle Hirnforschung. Experimentation cerebrale
Volume: 143
Issue: 4
ISSN: 0014-4819
Subject Category
Life Sciences (General)
Funding Number(s)
CONTRACT_GRANT: NGA 5 R01 DC04212
Distribution Limits
Public
Copyright
Other
Keywords
NASA Discipline Neuroscience
Non-NASA Center

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