Document Detail

Interactive effect of hypoxia and otolith organ engagement on cardiovascular regulation in humans.
MedLine Citation:
PMID:  12133867     Owner:  NLM     Status:  MEDLINE    
We determined the interaction between the vestibulosympathetic reflex and the arterial chemoreflex in 12 healthy subjects. Subjects performed three trials in which continuous recordings of muscle sympathetic nerve activity (MSNA), mean arterial blood pressure (MAP), heart rate (HR), and arterial oxygen saturation were obtained. First, in prone subjects the otolith organs were engaged by use of head-down rotation (HDR). Second, the arterial chemoreflex was activated by inspiration of hypoxic gas (10% O2 and 90% N2) for 7 min with HDR being performed during minute 6. Third, hypoxia was repeated (15 min) with HDR being performed during minute 14. HDR [means +/- SE; increase (Delta)7 +/- 1 bursts/min and Delta50 +/- 11% for burst frequency and total MSNA, respectively; P < 0.05] and hypoxia (Delta6 +/- 2 bursts/min and Delta62 +/- 29%; P < 0.05) increased MSNA. Additionally, MSNA increased when HDR was performed during hypoxia (Delta11 +/- 2 bursts/min and Delta127 +/- 57% change from normoxia; P < 0.05). These increases in MSNA were similar to the algebraic sum of the individual increase in MSNA elicited by HDR and hypoxia (Delta13 +/- 1 bursts/min and Delta115 +/- 36%). Increases in MAP (Delta3 +/- 1 mmHg) and HR (Delta19 +/- 1 beats/min) during combined HDR and hypoxia generally were smaller (P < 0.05) than the algebraic sum of the individual responses (Delta5 +/- 1 mmHg and Delta24 +/- 2 beats/min for MAP and HR, respectively; P < 0.05). These findings indicate an additive interaction between the vestibulosympathetic reflex and arterial chemoreflex for MSNA. Therefore, it appears that MSNA outputs between the vestibulosympathetic reflex and arterial chemoreflex are independent of one another in humans.
Kevin D Monahan; Chester A Ray
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  93     ISSN:  8750-7587     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  2002 Aug 
Date Detail:
Created Date:  2002-07-22     Completed Date:  2003-02-12     Revised Date:  2013-09-26    
Medline Journal Info:
Nlm Unique ID:  8502536     Medline TA:  J Appl Physiol (1985)     Country:  United States    
Other Details:
Languages:  eng     Pagination:  576-80     Citation Subset:  IM; S    
Department of Medicine, Division of Cardiology, General Clinical Research Center, Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033, USA.
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MeSH Terms
Anoxia / physiopathology*
Baroreflex / physiology*
Blood Pressure / physiology*
Head-Down Tilt
Muscle, Skeletal / innervation
Otolithic Membrane / physiology*
Sympathetic Nervous System / physiology*
Grant Support
C A Ray / PA St U Coll Med, Hershey

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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