Cortical GABA turnover during bicuculline seizures in rats

The rate of cortical gamma-aminobutyric acid (GABA) turnover was estimated by determining the rate of GABA accumulation following inhibition of GABA transaminase by gamma-vinyl-GABA (1.5 g/kg, i.v.) in paralysed, ventilated rats. During 1 h of bicuculline-induced seizures (1.2 mg/kg, i.v.) the rate of accumulation of cortical GABA level is approximately threefold greater than in the control group receiving gamma-vinyl-GABA alone, suggesting that the GABA shunt activity increases in parallel with the increase in overall cortical metabolic rate observed during bicuculline seizures. Pretreatment with gamma-vinyl-GABA did not affect the bicuculline-induced changes in other major cortical amino acids.