Effects of NMDA administration in the substantia nigra pars compacta on the striatal dopamine release before and after repetitive exposures to nitrogen narcosis in rats.

Full Abstract

Hyperbaric nitrogen-oxygen exposure developed in rats a decrement of the striatal dopamine release, which was reversed by repetitive exposures. This dopamine decrease could be the result of the antagonistic effect of nitrogen on NMDA receptors. The increment of the dopamine release, following repetitive exposures to nitrogen, could be attributed to a desensitisation of NMDA receptors to the effects of nitrogen. To test these hypotheses, male Sprague-Dawley rats were implanted with electrodes in the striatum to measure dopamine release by voltammetry and cannula in the substantia nigra pars compacta for NMDA injection. Free-moving rats were exposed up to 3MPa of nitrogen-oxygen mixture before and after 5 exposures to 1MPa. At the first exposure to 3MPa, the dopamine level decreased (-15%) but is counteracted by NMDA administration. In contrast, after repetitive exposure, the second exposure to 3MPa, induces a 10% dopamine increase. NMDA administration significantly potentiated this increase. Our results neither support the hypothesis of an antagonist effect of nitrogen on NMDA receptors at the first exposure, nor that of a NMDA receptor desensitization following repetitive exposures to hyperbaric nitrogen.

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Author information

Author/s: Lavoute, C (C); Weiss, M (M); Rostain, J C (JC);

Affiliation: Université de la Méditerranée et IMNSSA, EA 3280, Physiologie et Action Thérapeutique des Gaz Sous Pression, Institut Jean-Roche, Faculté de Médecine Nord, 13015 Marseille, France.

Journal and publication information

Publication Type: Journal Article; Research Support, Non-U.S. Gov't

Journal: Undersea & hyperbaric medicine : journal of the Undersea and Hyperbaric Medical Society, Inc (Undersea Hyperb Med), published in United States. (Language: eng)

Reference: -2006 May-Jun; vol 33 (issue 3) : pp 175-9

Dates: Created 2006/07/27; Completed 2006/08/08; Revised 2006/11/15;

PMID: 16869531, status: MEDLINE (last retrieval date: 12/26/2008)

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MeSH headings (categories)

This article was linked to the MESH Headings shown below.

Animals
Dopamine - metabolism
Excitatory Amino Acid Agonists - pharmacology
Inert Gas Narcosis - metabolism
Male

N-Methylaspartate - pharmacology
Rats
Rats, Sprague-Dawley
Receptors, N-Methyl-D-Aspartate - metabolism
Substantia Nigra - drug effects; metabolism

Associated Chemicals: Excitatory Amino Acid Agonists (0) ; Receptors, N-Methyl-D-Aspartate (0) ; Dopamine (51-61-6) ; N-Methylaspartate (6384-92-5)

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