Reduced GABA-mediated chloride flux in entorhinal cortex-kindled rat brains.

Gamma-aminobutyric acid (GABA)-mediated chloride uptake was determined in synaptoneurosomes prepared from the brains of entorhinal cortex-kindled and paired control rats. Subjects were sacrificed either 24 h or 28 days after the experimental animals had exhibited their sixth stage 5 convulsion. In the cortex and cerebellum, no difference was observed between kindled and control animals at either time period. In the brain-stem, however, a significant reduction (approximately 50%) in chloride uptake was observed in kindled subjects both 24 h and 28 days after the last seizure. These findings are consistent with the hypothesis that the 'kindled state' results from a long-lasting decrease in GABA-mediated inhibitory activity.