| Hypercapnic cerebral vascular reactivity is decreased, in humans, during sleep compared with wakefulness. | |
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MedLine Citation:
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PMID: 12576408 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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During wakefulness, increases in the partial pressure of arterial CO(2) result in marked rises in cortical blood flow. However, during stage III-IV, non-rapid eye movement (NREM) sleep, and despite a relative state of hypercapnia, cortical blood flow is reduced compared with wakefulness. In the present study, we tested the hypothesis that, in normal subjects, hypercapnic cerebral vascular reactivity is decreased during stage III-IV NREM sleep compared with wakefulness. A 2-MHz pulsed Doppler ultrasound system was used to measure the left middle cerebral artery velocity (MCAV; cm/s) in 12 healthy individuals while awake and during stage III-IV NREM sleep. The end-tidal Pco(2) (Pet(CO(2))) was elevated during the awake and sleep states by regulating the inspired CO(2) load. The cerebral vascular reactivity to CO(2) was calculated from the relationship between Pet(CO(2)) and MCAV by using linear regression. From wakefulness to sleep, the Pet(CO(2)) increased by 3.4 Torr (P < 0.001) and the MCAV fell by 11.7% (P < 0.001). A marked decrease in cerebral vascular reactivity was noted in all subjects, with an average fall of 70.1% (P = 0.001). This decrease in hypercapnic cerebral vascular reactivity may, at least in part, explain the stage III-IV NREM sleep-related reduction in cortical blood flow. |
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Authors:
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Guy E Meadows; Helen M A Dunroy; Mary J Morrell; Douglas R Corfield |
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Publication Detail:
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Type: Comparative Study; Journal Article; Research Support, Non-U.S. Gov't Date: 2003-02-07 |
Journal Detail:
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Title: Journal of applied physiology (Bethesda, Md. : 1985) Volume: 94 ISSN: 8750-7587 ISO Abbreviation: J. Appl. Physiol. Publication Date: 2003 Jun |
Date Detail:
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Created Date: 2003-05-08 Completed Date: 2003-07-23 Revised Date: 2006-11-15 |
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: 2197-202 Citation Subset: IM |
Affiliation:
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Department of Respiratory Medicine, National Heart and Lung Institute, Imperial College, Charing Cross Campus, London, W6 8RP, United Kingdom. guy.meadows@ic.ac.uk |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Adult Blood Flow Velocity Carbon Dioxide Cerebral Arteries / physiopathology Cerebrovascular Circulation* Female Heart Rate Humans Hypercapnia / physiopathology* Male Partial Pressure Sleep* Sleep Stages Tidal Volume Vasomotor System / physiopathology* Wakefulness* |
| Chemical | |
Reg. No./Substance:
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124-38-9/Carbon Dioxide |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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