Document Detail


Peripheral chemoreceptor control of ventilation following sustained hypoxia in young and older adult humans.
MedLine Citation:
PMID:  15258116     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The rate and duration of peripheral chemoreceptor resensitization following sustained hypoxia was characterized in young and older (74-year-old) adults. In addition, cerebral blood velocity (CBV) was measured in young subjects during and following the relief from sustained hypoxia. Following 20 min of sustained eucapnic hypoxia (50 mmHg), subjects were re-exposed to brief (1.5 min) hypoxic pulses (50 mmHg), and the magnitude of the ventilatory response was used to gauge peripheral chemosensitivity. Five minutes after the relief from sustained hypoxia, ventilation (V(E)) increased to 40.3 +/- 4.5% of the initial hypoxic ventilatory response, and by 36 min V(E) increased to 100%, indicating that peripheral chemosensitivity to hypoxia was restored. The V(E) response magnitude plotted versus time demonstrated that V(E), hence peripheral chemosensitivity, was restored at a rate of 1.9% per minute. Cerebral blood flow (CBF, inferred from CBV) remained constant during sustained hypoxia and increased by the same magnitude during the hypoxic pulses, suggesting that CBF has a small, if any, impact on the decline in V(E) during hypoxia and its subsequent recovery. To address the issue of whether hypoxic pulses affect subsequent challenges, series (continuous hypoxic pulses at various recovery intervals) and parallel (only 1 pulse per trial) methods were used. There were no differences in the ventilatory responses between the series and parallel methods. Older adults demonstrated a similar rate of recovery as in the young, suggesting that ageing in active older adults does not affect the peripheral chemoreceptor response.
Authors:
Andrea Vovk; W Donald F Smith; Nicole D Paterson; David A Cunningham; Donald H Paterson
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2004-07-15
Journal Detail:
Title:  Experimental physiology     Volume:  89     ISSN:  0958-0670     ISO Abbreviation:  Exp. Physiol.     Publication Date:  2004 Nov 
Date Detail:
Created Date:  2004-11-05     Completed Date:  2005-03-15     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  9002940     Medline TA:  Exp Physiol     Country:  England    
Other Details:
Languages:  eng     Pagination:  647-56     Citation Subset:  IM    
Affiliation:
Canadian Centre for Activity and Ageing, The University of Western Ontario, London, Ontario, Canada.
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MeSH Terms
Descriptor/Qualifier:
Adult
Aged
Aging*
Anoxia / physiopathology*
Blood Flow Velocity
Cerebrovascular Circulation
Chemoreceptor Cells / physiopathology*
Female
Humans
Male
Respiration*
Time Factors

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


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