Document Detail

Short-term intermittent hypoxia enhances sympathetic responses to continuous hypoxia in humans.
MedLine Citation:
PMID:  17556498     Owner:  NLM     Status:  MEDLINE    
Short-term intermittent hypoxia leads to sustained sympathetic activation and a small increase in blood pressure in healthy humans. Because obstructive sleep apnea, a condition associated with intermittent hypoxia, is accompanied by elevated sympathetic activity and enhanced sympathetic chemoreflex responses to acute hypoxia, we sought to determine whether intermittent hypoxia also enhances chemoreflex activity in healthy humans. To this end, we measured the responses of muscle sympathetic nerve activity (MSNA, peroneal microneurography) to arterial chemoreflex stimulation and deactivation before and following exposure to a paradigm of repetitive hypoxic apnea (20 s/min for 30 min; O(2) saturation nadir 81.4 +/- 0.9%). Compared with baseline, repetitive hypoxic apnea increased MSNA from 113 +/- 11 to 159 +/- 21 units/min (P = 0.001) and mean blood pressure from 92.1 +/- 2.9 to 95.5 +/- 2.9 mmHg (P = 0.01; n = 19). Furthermore, compared with before, following intermittent hypoxia the MSNA (units/min) responses to acute hypoxia [fraction of inspired O(2) (Fi(O(2))) 0.1, for 5 min] were enhanced (pre- vs. post-intermittent hypoxia: +16 +/- 4 vs. +49 +/- 10%; P = 0.02; n = 11), whereas the responses to hyperoxia (Fi(O(2)) 0.5, for 5 min) were not changed significantly (P = NS; n = 8). Thus 30 min of intermittent hypoxia is capable of increasing sympathetic activity and sensitizing the sympathetic reflex responses to hypoxia in normal humans. Enhanced sympathetic chemoreflex activity induced by intermittent hypoxia may contribute to altered neurocirculatory control and adverse cardiovascular consequences in sleep apnea.
Urs A Leuenberger; Cynthia S Hogeman; Sadeq A Quraishi; Sadeq Quraishi; Latoya Linton-Frazier; Kristen S Gray
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural     Date:  2007-06-07
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  103     ISSN:  8750-7587     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  2007 Sep 
Date Detail:
Created Date:  2007-08-28     Completed Date:  2007-12-20     Revised Date:  2014-01-10    
Medline Journal Info:
Nlm Unique ID:  8502536     Medline TA:  J Appl Physiol (1985)     Country:  United States    
Other Details:
Languages:  eng     Pagination:  835-42     Citation Subset:  IM    
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MeSH Terms
Anoxia / physiopathology*
Chemoreceptor Cells / physiology*
Hemodynamics / physiology
Hyperoxia / physiopathology
Oxygen / physiology
Pulmonary Ventilation / physiology
Sleep Apnea, Obstructive / physiopathology
Sympathetic Nervous System / physiopathology*
Time Factors
Grant Support
Reg. No./Substance:
Erratum In:
J Appl Physiol (1985). 2013 Nov;115(10):1581
Note: Quraishi, Sadeq [corrected to Quraishi, Sadeq A]

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