Document Detail

Reversible blunting of arousal from sleep in response to intermittent hypoxia in the developing rat.
MedLine Citation:
PMID:  20930126     Owner:  NLM     Status:  MEDLINE    
Arousal is an important survival mechanism when infants are confronted with hypoxia during sleep. Many sudden infant death syndrome (SIDS) infants are exposed to repeated episodes of hypoxia before death and have impaired arousal mechanisms. We hypothesized that repeated exposures to hypoxia would cause a progressive blunting of arousal, and that a reversal of this process would occur if the hypoxia was terminated at the time of arousal. P5 (postnatal age of 5 days), P15, and P25 rat pups were exposed to either eight trials of hypoxia (3 min 5% O(2) alternating with room air) (group A), or three hypoxia trials as in group A, followed by five trials in which hypoxia was terminated at arousal (group B). In both groups A and B, latency increased over the first four trials of hypoxia, but reversed in group B animals during trials 5-8. Progressive arousal blunting was more pronounced in the older pups. The effects of intermittent hypoxia on heart rate also depended on age. In the older pups, heart rate increased with each hypoxia exposure. In the P5 pups, however, heart rate decreased during hypoxia and did not return to baseline between exposures, resulting in a progressive fall of baseline values over successive hypoxia exposures. In the group B animals, heart rate changes during trials 1-4 also reversed during trials 5-8. We conclude that exposure to repeated episodes of hypoxia can cause progressive blunting of arousal, which is reversible by altering the exposure times to hypoxia and the period of recovery between hypoxia exposures.
R A Darnall; S McWilliams; R W Schneider; C M Tobia
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't     Date:  2010-10-07
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  109     ISSN:  1522-1601     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  2010 Dec 
Date Detail:
Created Date:  2010-12-14     Completed Date:  2011-03-25     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:  1686-96     Citation Subset:  IM    
Department of Pediatrics, Dartmouth School of Medicine, Lebanon, New Hampshire, USA.
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MeSH Terms
Age Factors
Animals, Newborn
Anoxia / blood,  physiopathology*
Body Temperature
Disease Models, Animal
Heart Rate
Infant, Newborn
Motor Activity
Oxyhemoglobins / metabolism
Reaction Time
Recovery of Function
Respiratory Rate
Sex Factors
Sudden Infant Death / etiology*
Time Factors
Grant Support
5P01 HD036379-12/HD/NICHD NIH HHS
Reg. No./Substance:

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