Document Detail


Comparison of nitrogen narcosis and helium pressure effects on striatal amino acids: a microdialysis study in rats.
MedLine Citation:
PMID:  18751893     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Exposure to nitrogen-oxygen mixture at high pressure induces narcosis, which can be considered as a first step toward general anaesthesia. Narcotic potencies of inert gases are attributed to their lipid solubility. Nitrogen narcosis induces cognitive and motor disturbances that occur from 0.3 MPa in man and from 1 MPa in rats. Neurochemical studies performed in rats up to 3 MPa have shown that nitrogen pressure decreases striatal dopamine release like argon, another inert gas, or nitrous oxide, an anaesthetic gas. Striatal dopamine release is under glutamatergic and other amino acid neurotransmission regulations. The aim of this work was to study the effects of nitrogen at 3 MPa on striatal amino acid levels and to compare to those of 3 MPa of helium which is not narcotic at this pressure, by using a new technique of microdialysis samples extraction under hyperbaric conditions, in freely moving rats. Amino acids were analysed by HPLC coupled to fluorimetric detection in order to appreciate glutamate, aspartate, glutamine and asparagine levels. Nitrogen-oxygen mixture exposure at 3 MPa decreased glutamate, glutamine and asparagine concentrations. In contrast, with helium-oxygen mixture, glutamate and aspartate levels were increased during the compression phase but not during the stay at maximal pressure. Comparison between nitrogen and helium highlighted the narcotic effects of nitrogen at pressure. As a matter of fact, nitrogen induces a reduction in glutamate and in other amino acids that could partly explain the decrease in striatal dopamine level as well as the motor and cognitive disturbances reported in nitrogen narcosis.
Authors:
Nicolas Vallée; Jean-Claude Rostain; Alain Boussuges; Jean-Jacques Risso
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't     Date:  2008-08-27
Journal Detail:
Title:  Neurochemical research     Volume:  34     ISSN:  1573-6903     ISO Abbreviation:  Neurochem. Res.     Publication Date:  2009 May 
Date Detail:
Created Date:  2009-03-20     Completed Date:  2009-06-03     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  7613461     Medline TA:  Neurochem Res     Country:  United States    
Other Details:
Languages:  eng     Pagination:  835-44     Citation Subset:  IM    
Affiliation:
Faculté de Médecine Nord, IFR de Neurosciences Jean-Roche, Université de la Méditerranée et Institut de Médecine Navale du Service de Santé des Armées, Physiologie et Physiopathologie en Conditions d'Oxygénation Extrêmes, Marseille cedex 20, France.
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MeSH Terms
Descriptor/Qualifier:
Amino Acids / metabolism*
Animals
Asparagine / metabolism
Aspartic Acid / metabolism
Corpus Striatum / metabolism*
Glutamic Acid / metabolism
Glutamine / metabolism
Helium*
Inert Gas Narcosis / metabolism*
Male
Microdialysis
Nitrogen*
Pressure
Rats
Rats, Sprague-Dawley
Chemical
Reg. No./Substance:
0/Amino Acids; 56-84-8/Aspartic Acid; 56-85-9/Glutamine; 56-86-0/Glutamic Acid; 7006-34-0/Asparagine; 7440-59-7/Helium; 7727-37-9/Nitrogen

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


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