[abstract] DECREASED BRAIN DOPAMINE IN PATHOGENESIS OF HIGH PRESSURE OXYGEN INDUCED CONVULSIONS. ANTAGONIST EFFECT OF PROTECTIVE DRUGS

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[abstract] DECREASED BRAIN DOPAMINE IN PATHOGENESIS OF HIGH PRESSURE OXYGEN INDUCED CONVULSIONS. ANTAGONIST EFFECT OF PROTECTIVE DRUGS

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Title: [abstract] DECREASED BRAIN DOPAMINE IN PATHOGENESIS OF HIGH PRESSURE OXYGEN INDUCED CONVULSIONS. ANTAGONIST EFFECT OF PROTECTIVE DRUGS
Author: Brue, F; Dumas, C; Chaumont, A; Obrenovitch, T; Joanny, P
Abstract: After various treatments, mice were exposed in air 1 ATA, 02 6 ATA (HPO) or N2 + 02 6 ATA (P 02 = 0.21 atm), and sacrificed at pressure by deep-freezing in liquid nitrogen. Before onset of generalized convulsions, brain DA and NA were significantly decreased in controls under HPO. HPN2 had no effect. 61 mg. kg-1 of pargyline, an inhibitor of MAO, abolishes the hyperoxic decrease of brain catecholamines levels. 200 mg. kg-1 of a-methyl-p-tyrosine, an inhibitor of the biosynthetic enzyme tyrosine hydroxylase, lacks to modify the effect of HPO. Decreased DA and NA levels seem to be due to stimulation of release or rather of inactivation of catecholamine under HPO. The best protectors suitable against HPO toxicity tested in mice, clonazepam (0. 1 mg. kg-] ) , diazepam (1 mg. kg-1) , and gamma-hydroxybutyrate (125 mg. kg-]) delay the hyperoxic fall of brain DA, and sometimes of brain NA. At the onset of the convulsions after various exposure times, brain catecholamines are equally diminished in control and treated mice. L -dopa (50 mg. kg-1) delays the onset of convulsions. Considering the inhibitory neurotransmitter effect of DA and the concentration of DA in substantia nigra and in nigral projections to the cerebral cortex and to the basal ganglia complex, ascending and descending pathways originating in substancia nigra may be involved in the failure of control of cortical and spinal motoneurone activity under HPO.
Description: Abstract of the Undersea and Hyperbaric Medical Society, Inc. Annual Scientific Meeting held May 13-16, 1977. Holiday-Inn, Toronto, Ontario, Canada (http:www.uhms.org)
URI: http://archive.rubicon-foundation.org/4190
Date: 1977

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  • UHMS Meeting Abstracts
    This is a collection of the published abstracts from the Undersea and Hyperbaric Medical Society (UHMS) annual meetings.

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