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Nitric oxide amplifies the excitatory to inhibitory neurotransmitter imbalance accelerating oxygen seizures.

Publication ,  Journal Article
Demchenko, IT; Piantadosi, CA
Published in: Undersea Hyperb Med
2006

CNS O2 toxicity is manifested most profoundly by generalized motor convulsions. The hypothesis was tested that HBO2 triggers seizures by an excitatory to inhibitory neurotransmitter imbalance produced by neuronal nitric oxide (NO) activity. Anesthetized rats were exposed to 5 ATA HBO2 for 75 min with or without prior inhibition of nNOS. Interstitial NO and amino acids: aspartate (Asp), glutamate (Glu) and gamma-aminobutyric acid (GABA) were determined in the striatum by microdialysis coupled with HPLC. Blood flow and EEG in the same striatal region were measured simultaneously. Rats treated with 7-NI showed no EEG spikes of O2 toxicity, while seizure latency for untreated rats was 63 +/- 7 min. Significant increases in NO metabolites and blood flow were observed in control rats before seizures. HBO2 did not change Glu significantly and increased Asp slightly whereas GABA decreased progressively by 37 +/- 7%. Pretreatment with 7-NI led to a significantly smaller decline in GABA. Overall, the simplified excitotoxicity index Glu/GABA increased significantly after 60 min of HBO2 in control but fell in rats treated with 7-NI. We conclude that HBO2-stimulated neuronal NO production promotes an imbalance between glutamatergic and GABAergic synaptic function implicated in the genesis of oxygen-induced seizures.

Duke Scholars

Published In

Undersea Hyperb Med

ISSN

1066-2936

Publication Date

2006

Volume

33

Issue

3

Start / End Page

169 / 174

Location

United States

Related Subject Headings

  • gamma-Aminobutyric Acid
  • Rats, Sprague-Dawley
  • Rats
  • Physiology
  • Nitric Oxide Synthase Type I
  • Nitric Oxide
  • Male
  • Hyperbaric Oxygenation
  • High Pressure Neurological Syndrome
  • Glutamic Acid
 

Citation

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Demchenko, I. T., & Piantadosi, C. A. (2006). Nitric oxide amplifies the excitatory to inhibitory neurotransmitter imbalance accelerating oxygen seizures. Undersea Hyperb Med, 33(3), 169–174.
Demchenko, I. T., and C. A. Piantadosi. “Nitric oxide amplifies the excitatory to inhibitory neurotransmitter imbalance accelerating oxygen seizures.Undersea Hyperb Med 33, no. 3 (2006): 169–74.
Demchenko, I. T., and C. A. Piantadosi. “Nitric oxide amplifies the excitatory to inhibitory neurotransmitter imbalance accelerating oxygen seizures.Undersea Hyperb Med, vol. 33, no. 3, 2006, pp. 169–74.
Demchenko IT, Piantadosi CA. Nitric oxide amplifies the excitatory to inhibitory neurotransmitter imbalance accelerating oxygen seizures. Undersea Hyperb Med. 2006;33(3):169–174.

Published In

Undersea Hyperb Med

ISSN

1066-2936

Publication Date

2006

Volume

33

Issue

3

Start / End Page

169 / 174

Location

United States

Related Subject Headings

  • gamma-Aminobutyric Acid
  • Rats, Sprague-Dawley
  • Rats
  • Physiology
  • Nitric Oxide Synthase Type I
  • Nitric Oxide
  • Male
  • Hyperbaric Oxygenation
  • High Pressure Neurological Syndrome
  • Glutamic Acid