[abstract] EFFECTS OF REPEATED EXPOSURES TO PRESSURE WHICH INDUCED NITROGEN NARCOSIS ON THE STRIATAL DOPAMINE RELEASE AND ON MOTOR DISTURBANCES IN THE RATS

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[abstract] EFFECTS OF REPEATED EXPOSURES TO PRESSURE WHICH INDUCED NITROGEN NARCOSIS ON THE STRIATAL DOPAMINE RELEASE AND ON MOTOR DISTURBANCES IN THE RATS

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Title: [abstract] EFFECTS OF REPEATED EXPOSURES TO PRESSURE WHICH INDUCED NITROGEN NARCOSIS ON THE STRIATAL DOPAMINE RELEASE AND ON MOTOR DISTURBANCES IN THE RATS
Author: Lavoute, C; Weiss, M; Sainty, JM; Rostain, JC
Abstract: BACKGROUND: Divers exposed to hyperbaric nitrogen-oxygen mixture develop from about 4ATA, narcosis composed by motor and cognitive disturbances. In rats, behavioural and neurochemical effects of nitrogen exposure up to 31ATA indicate an enhancement of motor activities and a decrement of the dopamine release in the striatum. Moreover, adaptation to the signs and symptoms of narcosis were subjectively reported during repetitive dives. This study examines the physiological effects of repetitive exposures nitrogen-oxygen pressures which induce narcosis. MATERIALS AND METHODS: Under general anesthesia, male Sprague-Dawley rats were implanted in the striatum with multifiber carbon dopamine-sensitive electrodes. After recovery from surgery, awake free-moving rats were exposed for 2 hours up to 31ATA of nitrogen-oxygen mixture before and after one daily exposure to 11ATA of nitrogen-oxygen, for 5 consecutive days. Dopamine release was measured by differential pulse voltametry and motor activities or disturbances were quantified using piezo-electric captor. RESULTS: At the first exposure to 31ATA, the striatal dopamine level decreased during the compression (-15percent) to reach -20percent during the stay at pressure. Motor disturbances were increased during compression (+15percent) and the first 60 min at constant pressure (+10percent). In contrast, at the second exposure to 31ATA, an increase of dopamine of +15percent was obtained during the whole exposure. However, the level of global motor activities recorded by piezo-electric captor remained unchanged as compared to the first exposure. CONCLUSION: Our results confirm that nitrogen exposure at 3 MPa led to a decreased striatal dopamine release and increased motor disturbances in naive rats. Repetitive exposures to 11ATA of nitrogen induced a reversal effect on the dopamine release which suggested changes in the neurochemical mechanisms involved in the dopamine release at the level of the nigro-striatal pathway. In contrast, the level of motor activity remained unchanged, thus suggesting the possible involvement of other neurotransmissions. (Research supported by a grant DGA "PEA980809)
Description: Undersea and Hyperbaric Medical Society, Inc. (http://www.uhms.org )
URI: http://archive.rubicon-foundation.org/1767
Date: 2005

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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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