Document Detail

Mechanism for changes in vasopressin during acute exposure at 3 atm abs air.
MedLine Citation:
PMID:  9249558     Owner:  NLM     Status:  MEDLINE    
Plasma arginine vasopressin (AVP) concentration is reduced in human subjects during prolonged saturation dive exposures of 4 atmospheres absolute (atm abs) and greater. The objectives of the present study were to determine if AVP would be reduced in eight male subjects during a 1-h exposure of 3 atm abs air and, if so, to determine the mechanisms responsible for the AVP response. Assessments of transmural central venous pressure (central venous pressure-esophageal pressure) and cardiac volume measurements were made to evaluate the possible role of cardiopulmonary receptors on the AVP response. Also, plasma osmolality (P(osmol)), venous blood gases, and mean corpuscular volume (MCV) were determined to evaluate potential effects of osmoreceptor and other fluid shifts on AVP release. AVP decreased (P < 0.05) by 0.5 microU/ml at 3 atm abs, whereas the transmural central venous pressure and cardiac volume remained unchanged throughout the experimental periods. A significant reduction (P < 0.05) in P(osmol) (by approximately 3 mosmol/kgH2O) was detected at 3 atm abs. Therefore, we conclude that the reduction in P(osmol) may cause the reduction in AVP during exposure to 3 atm abs pressure. The reduction in P(osmol) without water intake requires the postulation of an internal source of water. We propose that the threefold increase (P < 0.01) in venous PO2 and concomitant decrease (P < 0.05) in venous MCV suggest that the red blood cell may contribute to hypotonicity at 3 atm abs.
R Torii; S Sagawa; F Wada; K Nagaya; Y Endo; F Yamazaki; T Nakamura; J R Claybaugh; K Shiraki
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.    
Journal Detail:
Title:  The American journal of physiology     Volume:  273     ISSN:  0002-9513     ISO Abbreviation:  Am. J. Physiol.     Publication Date:  1997 Jul 
Date Detail:
Created Date:  1997-09-03     Completed Date:  1997-09-03     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  0370511     Medline TA:  Am J Physiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  R259-64     Citation Subset:  IM    
Department of Physiology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan.
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MeSH Terms
Acid-Base Equilibrium*
Air Pressure*
Arginine Vasopressin / blood,  secretion*
Bicarbonates / blood
Blood Pressure
Carbon Dioxide / blood
Central Venous Pressure
Erythrocyte Volume
Esophagus / physiology
Heart Atria
Heart Rate
Hemoglobins / analysis
Hydrogen-Ion Concentration
Oxygen / blood
Plasma Volume
Pressoreceptors / physiology
Stroke Volume
Reg. No./Substance:
0/Bicarbonates; 0/Hemoglobins; 113-79-1/Arginine Vasopressin; 124-38-9/Carbon Dioxide; 7782-44-7/Oxygen

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