Status epilepticus increases the intracellular accumulation of GABAA receptors.

Status epilepticus is a neurological emergency that results in mortality and neurological morbidity. It has been postulated that the reduction of inhibitory transmission during status epilepticus results from a rapid modification of GABA(A) receptors. However, the mechanism(s) that contributes to this modification has not been elucidated. We report, using an in vitro model of status epilepticus combined with electrophysiological and cellular imaging techniques, that prolonged epileptiform bursting results in a reduction of GABA-mediated synaptic inhibition. Furthermore, we found that constitutive internalization of GABA(A) receptors is rapid and accelerated by the increased neuronal activity associated with seizures. Inhibition of neuronal activity reduced the rate of internalization. These findings suggest that the rate of GABA(A) receptor internalization is regulated by neuronal activity and its acceleration contributes to the reduction of inhibitory transmission observed during prolonged seizures.