| Short-term intermittent hypoxia enhances sympathetic responses to continuous hypoxia in humans. | |
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MedLine Citation:
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PMID: 17556498 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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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. |
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Authors:
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Urs A Leuenberger; Cynthia S Hogeman; Sadeq Quraishi; Latoya Linton-Frazier; Kristen S Gray |
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Publication Detail:
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Type: Journal Article; Research Support, N.I.H., Extramural Date: 2007-06-07 |
Journal Detail:
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Title: Journal of applied physiology (Bethesda, Md. : 1985) Volume: 103 ISSN: 8750-7587 ISO Abbreviation: J. Appl. Physiol. Publication Date: 2007 Sep |
Date Detail:
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Created Date: 2007-08-28 Completed Date: 2007-12-20 Revised Date: 2008-11-21 |
Medline Journal Info:
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Nlm Unique ID: 8502536 Medline TA: J Appl Physiol Country: United States |
Other Details:
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Languages: eng Pagination: 835-42 Citation Subset: IM |
Affiliation:
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Division of Cardiology, MC H047, Heart & Vascular Institute, The Pennsylvania State University College of Medicine, The Milton S. Hershey Medical Center, P.O. Box 850, Hershey, PA 17033, USA. uleuenberger@psu.edu |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Adult Anoxia / physiopathology* Chemoreceptor Cells / physiopathology* Female Hemodynamics / physiology Humans Hyperoxia / physiopathology Male Oxygen / physiology Pulmonary Ventilation / physiology Sleep Apnea, Obstructive / physiopathology Sympathetic Nervous System / physiopathology* Time Factors |
| Grant Support | |
ID/Acronym/Agency:
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M01-RR-010732/RR/NCRR NIH HHS; P01-HL-077670/HL/NHLBI NIH HHS; R01-HL-068699/HL/NHLBI NIH HHS |
| Chemical | |
Reg. No./Substance:
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7782-44-7/Oxygen |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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