Sensitivity of GABA synthesis in human brain to oxygen poisoning

Homogenates were prepared from the basal ganglia and frontal cortex of human brain and incubated for 20 min of 25 degrees C under either 1 ATA N2 or 3 ATA O2 (OHP). Exposure of the homogenates to OHP caused a significant inhibition in the activity of the gamma-aminobutyric acid (GABA) synthesising enzyme, glutamic acid decarboxylase. This finding, together with previously published data on animal experiments, suggests that a deranged GABA metabolism must be given serious consideration as a possible mechanism for OHP-induced seizures in man.