Document Detail


Ventilatory and metabolic responses to cold and hypoxia in intact and carotid body-denervated rats.
MedLine Citation:
PMID:  1400048     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The effects of hypoxia on thermoregulation and ventilatory control were studied in conscious rats before and after carotid denervation (CD). Measurements of metabolic rate (VO2), ventilation (V), shivering intensity (SI), and colonic temperature (Tc) were made in groups of eight rats subjected to three protocols. In protocols 1 and 2, at ambient temperature (Ta) of 25 and 5 degrees C, respectively, rats were exposed to normoxia and hypoxia [inspired O2 fraction (FIO2) 0.13-0.11]. In protocol 3, Ta was decreased from 25 to 5 degrees C in 30-min steps of 5 degrees C. Recordings were made in normoxia and hypoxia (FIO2 0.12). The results show that in both intact and CD rats 1) in normoxia, cold exposure increased VO2, V, and SI, and these increases were proportional to the decrease in Ta; 2) hypoxia induced only a transient decrease in SI, and, for a given Ta, VO2 was reduced whereas V and SI were increased; and 3) in CD rats, V increased less during cold exposure in both normoxia and hypoxia; VO2 and Tc were more depressed during hypoxia. It is concluded that 1) the interaction between Ta and FIO2 in the control of V is partly dependent on the carotid body afferents, 2) shivering thermogenesis may be transiently affected by hypoxia independently of the carotid body afferents, and 3) nonshivering thermogenesis may be directly inhibited by hypoxia, especially during cold exposure.
Authors:
H Gautier; M Bonora
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  73     ISSN:  8750-7587     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  1992 Sep 
Date Detail:
Created Date:  1992-11-23     Completed Date:  1992-11-23     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:  847-54     Citation Subset:  IM; S    
Affiliation:
Laboratoire de Physiologie Respiratoire, Faculté de Médecine Saint-Antoine, Paris, France.
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MeSH Terms
Descriptor/Qualifier:
Afferent Pathways / physiology
Animals
Anoxia / physiopathology*
Body Temperature Regulation / physiology
Carotid Body / physiology*
Cold Temperature / adverse effects*
Denervation
Female
Oxygen Consumption / physiology
Rats
Rats, Wistar
Reflex / physiology
Respiratory Mechanics / physiology*
Shivering / physiology

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


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