The close relationship between decreases in extracellular GABA concentrations and increases in the incidence of hyperbaric oxygen-induced electrical discharge

Shan Zhang, Yoshimasa Takeda, Shingo Hagioka, Keiji Goto, Kiyoshi Morita

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)

Abstract

To elucidate the mechanism by which hyperbaric oxygen (HBO2) induces electrical discharge, changes in the extracellular concentrations of GABA and glutamate were measured every 5 min using a microdialysis technique in rats during a period of exposure to HBO2 (5 atm abs). Electrical discharge was observed at 28 ± 4 min after the onset of exposure. Though the extracellular concentrations of glutamate remained unchanged, the extracellular GABA concentrations (pre-exposure level, 0.026 ± 0.005 μM in dialysate) began to decrease 15 min after the onset of exposure and reached their lowest level (74 ± 14%, 0.019 ± 0.004 μM) at the time of appearance of the discharge. There was a close logistic relationship between extracellular GABA concentrations and the discharge incidence, and the extracellular concentrations of GABA causing electrical discharge in 50% of the animals were estimated to be 80% of the pre-exposure level. These results suggest a possible mechanism that HBO2 exposure-induced discharge is caused by the decrease in extracellular concentration of GABA.

Original languageEnglish
Pages (from-to)91-95
Number of pages5
JournalActa medica Okayama
Volume58
Issue number2
Publication statusPublished - Apr 1 2004

Keywords

  • Gamma-aminobutyric acid
  • Glutamic acid
  • Hyperbaric oxygenation
  • Microdialysis
  • Seizures

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)

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