Study on hyperbaric oxygen-induced convulsion with particular reference to gamma-aminobutyric acid in synaptosomes.

When mice were exposed to 100% oxygen at a pressure of 6 atm. absolute, the animals suffered from severe convulsions. The content of gamma-aminobutyric acid (GABA) in synaptosomes was lower in the exposed animals than in unexposed ones. The exposure to high pressure oxygen produced a considerable reduction in GABA formation rate in synaptosomes, due to the inhibition of glutamic acid decarboxylase activity. Exposure to air at the same high pressure produced no reduction in the GABA levels in synaptosomes. The results support the view that low GABA levels in synaptosomes were involved in the etiology of the seizures.