Sensitivity of the rat hippocampal GABAA receptor α4 subunit to electroshock seizures

The effects of one and five electroshock seizures on [H-3]flunitrazepam binding, diazepam-insensitive (DIS) [H-3]Ro 15-4513 binding, and levels of mRNA for GABA(A) receptor alpha 1, alpha 4, beta 3 and gamma 2 subunits were examined in rats. No changes in any parameter were observed in the CA1 region of hippocampus or in parietal cortex. However, a single seizure produced a rapid and transient increase of alpha 4 mRNA in the dentate gyrus, without altering the expression of the other subunits. The putative alpha 4 protein, as measured by DIS [H-3]Ro 15-4513 binding, was also elevated in the dentate gyrus by a single shock. Repeated electroshock (48-h intervals) resulted in an enhanced response of the alpha 4 subunit to the seizure. Neither one nor five seizures altered [H-3]flunitrazepam binding. (C) 1998 Published by Elsevier Science Ireland Ltd. All rights reserved.