[abstract] BEHAVIORAL COMPARISON BETWEEN NITROULS OXIDE AND NITROGEN NARCOSIS

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[abstract] BEHAVIORAL COMPARISON BETWEEN NITROULS OXIDE AND NITROGEN NARCOSIS

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Title: [abstract] BEHAVIORAL COMPARISON BETWEEN NITROULS OXIDE AND NITROGEN NARCOSIS
Author: Turle-Lorenzo, N; Saget, A; Meliet, JL; Menu, JP; Risso, JJ
Abstract: BACKGROUND: Narcosis is a neurological syndrome decreasing operational capacities of divers between 30 m and 100 m. Although the psychosensorimotor symptoms of nitrogen narcosis are well known, the neurochemical mechanisms are not yet elucidated. The main goal of this study is to compare the behavioural as well as the neurochemical effects of a normobaric narcosis under several percentage of N2O and those of a hyperbaric narcosis, under 0.9 Mpa of Nitrox, in order to establish a normobaric model of narcosis. MATERIAL AND METHODS: Microdialysis, as a direct and dynamic technique, has been chosen to monitor changes in extracellular cerebral neurotransmitters, in rats striatum and accumbens nucleus. Behavioural studies have been performed simultaneously, in the same animals realising fixed-ratio test. A 50percent percentage of normoxic N2O has been compared to a 0.9 Mpa normoxic Nitrox mixture. Behavioural data characterized by number of lever press, locomotor activity and rearings have been recorded. RESULTS: Under normobaric narcosis, rats (n=10) present a decrease in the number of lever press by 70percent (p less than 0.01, Wilcoxon test). Under 0.9 Mpa of Nitrox mixture, a decrease in response rate of 50percent (p less than 0.05, Wilcoxon test) was noticed. Concerning the reaction time, the first lever pression delay increased by a factor 2 under 0.9 Mpa Nitrox versus a factor 3 under normobaric 50percent N2O (p less than 0.01). The last lever pression delay also increases by 2.5 under N2O (p less than 0.01) and by 2 under hyperbaric narcosis (p less than 0.05). The number of rearings were significantly decreased by 90percent under 50percent of N2O as well as under hyperbaric Nitrox. CONCLUSION: Behavioural results obtained in this study confirm neurochemical results indicating that the alterations obtained under 50percent N2O are similar to those obtained under hyperbaric nitrogen. Consequently, Nitrous oxide could be considered as a normobaric model of hyperbaric narcosis.
Description: Undersea and Hyperbaric Medical Society, Inc. (http://www.uhms.org )
URI: http://archive.rubicon-foundation.org/776
Date: 1999

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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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