Document Detail


Oxygen consumption of the chicken embryo: interaction between temperature and oxygenation.
MedLine Citation:
PMID:  15733783     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
We measured the effects of hypoxia and changes in ambient temperature (T) on the oxygen consumption (VO2) of chicken embryos at embryonic days 11, 16 and 20 (E11, E16 and E20, respectively), and post-hatching day 1 (H1). Between 30 and 39 degrees C, at E11 and E16, VO2 changed linearly with T, as in ectothermic animals, with a Q10 of about 2.1. At E20, VO2 did not significantly change with T, indicating the onset of endothermy. At H1, a drop in T increased VO2, a clear thermogenic response. Hypoxia (11% O2 for 30 min) decreased VO2, by an amount that varied with T and age. At H1, hypoxia lowered VO2 especially at low T. At E20, hypoxic hypometabolism was similar at all T. At E11 and E16, hypoxia lowered VO2 only at the higher T. In fact, at E11, with T=39 degrees C even a modest hypoxia (15-18% O2) decreased VO2. Upon return to normoxia after 40 min of 11% O2, VO2 did not rise above the pre-hypoxic level, indicating that the hypometabolism during hypoxia did not generate an O2 debt. At E11, during modest hypoxia (16% O2) at 36 degrees C, the drop in VO2 was lifted by raising the T to 39 degrees C, suggesting that the hypoxic hypometabolism at 36 degrees C was not due to O2-supply limitation. In conclusion, the hypometabolic effects of hypoxia on the chicken embryo's VO2 depend on the development of the thermogenic ability, occurring predominantly at high T during the early (ectothermic phase) and at low T during the late (endothermic) phase. At E11, both low T and low oxygen force VO2 to drop. However, at a near-normal T, modest hypoxia promotes a hypometabolic response with the characteristics of regulated O2 conformism.
Authors:
Jacopo P Mortola; Katherine Labbè
Related Documents :
19091913 - Hypercapnic vs. hypoxic control of cardiovascular, cardiovagal, and sympathetic function.
16185143 - Acute effect of exercise-hypoxia challenge on glut4 protein expression in rat cardiac m...
8283603 - Comparison of adenosine and treadmill exercise thallium-201 stress tests for the detect...
Publication Detail:
Type:  Comparative Study; Journal Article    
Journal Detail:
Title:  Respiratory physiology & neurobiology     Volume:  146     ISSN:  1569-9048     ISO Abbreviation:  Respir Physiol Neurobiol     Publication Date:  2005 Mar 
Date Detail:
Created Date:  2005-02-28     Completed Date:  2005-05-02     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  101140022     Medline TA:  Respir Physiol Neurobiol     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  97-106     Citation Subset:  IM    
Affiliation:
Department of Physiology, McGill University, 3655 Sir William Osler Promenade, Montreal, Que., Canada H3G 1Y6. jacopo.mortola@mcgill.ca
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Descriptor/Qualifier:
Age Factors
Analysis of Variance
Animals
Animals, Newborn
Anoxia / metabolism,  physiopathology
Blood Gas Analysis / methods
Body Temperature
Body Weight
Calorimetry / methods
Chick Embryo
Monitoring, Physiologic
Oxygen Consumption / physiology*
Pulmonary Gas Exchange / physiology
Respiration*
Temperature*
Time Factors

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


Previous Document:  Training to yoga respiration selectively increases respiratory sensation in healthy man.
Next Document:  Imaging iron stores in the brain using magnetic resonance imaging.