[abstract] PEROXYNITRITE PRODUCTION IN HYPERBARIC OXYGEN-INDUCED NEUROTOXICITY.

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[abstract] PEROXYNITRITE PRODUCTION IN HYPERBARIC OXYGEN-INDUCED NEUROTOXICITY.

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Title: [abstract] PEROXYNITRITE PRODUCTION IN HYPERBARIC OXYGEN-INDUCED NEUROTOXICITY.
Author: Demchenko, IT; Boso, AF; Doar, PO; Bennett, PB; Piantadosi, CA
Abstract: BACKGROUND: Nitric oxide (NO) and its metabolites may contribute to hyperbaric oxygen (HBO2) neurotoxicity by several mechanisms. We have tested the hypothesis that peroxynitrite (ONOO-), a reaction product of NO and superoxide anion, is involved in HBO2-induced neurotoxicity. METHODS: Anesthetized SD rats were exposed to O2 at 5 or 6 ATA. CBF and PO2 in the right striatum were measured by hydrogen clearance and platinum needle elctrodes. NO metabolites (NOx) and 3-nitrotyrosine (3-NT), as indicators of NO and ONOO- formation were measured in left striatum by microdialysis and anayzed by chemiluminescence and HPLC respectively. Blood pressure, EEG and temperature were monitored. All measurements were made during HBO-exposure with or without administration of NOS inhibitors (L-NAME, 7-NI) and ONOO-scavengers (SeM, Ebselen). RESULTS: The changes in CBF, PO2 EEG, NOx and 3-NT were HBO pressure and time dependent. At 5 ATA CBF and NOx initially decreased but then returned to control levels before the onset of EEG discharges. 3-NT gradually increased during HBO exposure at 5 ATA. At 6 ATA, CBF, NOx and 3-NT dramatically increased during 10 min HBO exposure. Rats pretreated with L-NAME or 7-NI before hyperbaric oxygen exposure maintained a low CBF and did not show changes in NOx and 3-NT. Administration of ONOO- scavengers did not prevent HBO induced CBF responses but decreased 3-NT level and prevented the EEG signs ofoxygen toxicity. CONCLUSION: HBO induces brain formation of reactive oxygen and nitrogen species implicated in ONOO- production prior to the appearance of EEG signs of oxygen neurotoxicity.
Description: Undersea and Hyperbaric Medical Society, Inc. (http://www.uhms.org)
URI: http://archive.rubicon-foundation.org/6687
Date: 2000

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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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