GABA(A) receptor internalization during seizures

Abstract

A rapid modification in the postsynaptic gamma-aminobutyric acid (GABA(A)) receptor population occurs during the prolonged seizures of status epilepticus (SE). This rapid modification contributes to a reduction in GABA-mediated inhibition and the development of benzodiazepine pharmacoresistance. Previous hypotheses to explain the modification have included an alteration in the structural composition or posttranslational modification of the receptors. In a cultured hippocampal neuron model, we found that there was differential subcellular distribution of GABA(A) receptor subunits and that the constitutive internalization of GABA(A) receptors containing a beta2/3 subunit was rapid and activity-dependent. Based on this finding, we posit that an activity-dependent increase in the rate of internalization of synaptic GABA(A) receptors during SE contributes to the reduction in inhibitory transmission and the development of benzodiazepine pharmacoresistance.