Document Detail

Energy expenditure and blood flows in thermoregulatory organs during microgravity simulation in rat. Emphasis on the importance of the control group.
MedLine Citation:
PMID:  11867294     Owner:  NLM     Status:  MEDLINE    
Rat tail suspension is commonly used to mimic human physiology in space. However, energy metabolism adaptation and related autonomic responses are unknown. To give new insights in energy homeostasis, we determined total energy expenditure (TEE) and blood flow redistribution in thermoregulatory organs during suspension using two control groups of animals widely accepted in the literature: the individually housed (isolated) and restraint rats (horizontally attached to the suspension device). Rats (n=33) were randomly assigned during 14-days to three experimental groups: isolated, suspended, or attached. TEE was assessed by a doubly labeled water method throughout the 14 days, and regional blood flow by radiolabeled microsphere procedure at the end of the protocol. Attachment vs. suspension resulted in a significant decrease in TEE (25%), skin (54%), adrenal (55%) and kidney (42%) blood flows, cardiac index (33%), and plasma corticosterone (50%), whereas total peripheral resistances increased (50%). Isolation vs. attachment triggered an inverse response, of similar amplitude, for all above variables. By comparing isolation and suspension, no overall effect was observed. The striking conclusion of this study is that no clear conclusion can be drawn. The choice of the isolated or attached animals as control profoundly influences the outcome results regarding the effects of simulated weightlessness. Further studies are needed but we favor the attached group as the true control since, from a theoretical point of view, a suspended rat is attached plus suspended. In such conditions, TEE decreases to the same extent in rat and humans during simulated microgravity. When reviewing published experiments, we recommend special attention to the control group used rather than on the effects of suspension as compared to an undefined control.
Stéphane Blanc; Sylvie Normand; Christiane Pachiaudi; Guillemette Gauquelin-Koch; Claude Gharib; Laurence Somody
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Comparative biochemistry and physiology. Part A, Molecular & integrative physiology     Volume:  131     ISSN:  1095-6433     ISO Abbreviation:  Comp. Biochem. Physiol., Part A Mol. Integr. Physiol.     Publication Date:  2002 Mar 
Date Detail:
Created Date:  2002-02-27     Completed Date:  2002-07-25     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  9806096     Medline TA:  Comp Biochem Physiol A Mol Integr Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  683-95     Citation Subset:  IM; S    
Laboratoire de Physiologie de l'Environnement, Faculté de Médecine Lyon Grange-Blanche, 8 avenue Rockefeller, 69373 Lyon Cedex 08, France.
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MeSH Terms
Body Temperature Regulation / physiology*
Body Weight
Cardiovascular Physiological Phenomena
Corticosterone / blood
Energy Metabolism / physiology*
Hindlimb Suspension / physiology*
Organ Size
Rats, Wistar
Regional Blood Flow / physiology
Vascular Resistance / physiology
Reg. No./Substance:

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