Document Detail

The effect of gravity on the response of ventilation to abrupt change in FICO2.
MedLine Citation:
PMID:  3124239     Owner:  NLM     Status:  MEDLINE    
Recently, Arieli and Farhi (1987) formulated a model for a previous suggestion made by their group that an increased ventilation as gravity increases is due to reduced perfusion of the respiratory center which causes an elevation of tissue PCO2. Extending the model to the dynamic response, we predict a slower ventilatory response to CO2 breathing as gravity increases. To test this prediction, ventilatory response to 5% CO2 was studied in 11 seated subjects at +1 and +2 Gz in a human centrifuge. Five of these subjects were studied at +3 Gz as well. In addition, ventilatory response to 5% CO2, using breath-by-breath analysis, was measured in three subjects in supine and upright postures. The ventilatory response (mainly through tidal volume) was faster as gravity increased from +1 to +2 and to +3 Gz, and from supine to the upright position. These findings disagree with the model prediction. Therefore, an alternative explanation is suggested based on the response of CO2 sensitive stretch receptors in the lung. Increased gravity causes increased ventilation, reduction of cardiac output and increased VA/Q mismatch; all enlarge the part of the lung with low CO2 where responsiveness of the CO2 sensitive stretch receptors is large.
R Arieli; D W Cugell; U Boutellier; N Gavriely; A E Rubin
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Respiration physiology     Volume:  71     ISSN:  0034-5687     ISO Abbreviation:  Respir Physiol     Publication Date:  1988 Feb 
Date Detail:
Created Date:  1988-03-04     Completed Date:  1988-03-04     Revised Date:  2009-11-11    
Medline Journal Info:
Nlm Unique ID:  0047142     Medline TA:  Respir Physiol     Country:  NETHERLANDS    
Other Details:
Languages:  eng     Pagination:  247-57     Citation Subset:  IM; S    
Israel Naval Hyperbaric Institute, Israel Oceanographic & Limnological Research, Haifa.
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MeSH Terms
Carbon Dioxide / pharmacology*
Middle Aged
Models, Biological
Respiration / drug effects*
Tidal Volume
Reg. No./Substance:
124-38-9/Carbon Dioxide

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