Autoradiographic analysis of [35S]TBPS binding in entorhinal cortex-kindled rat brains.

A quantitative autoradiographic analysis of [35S]t-butylbicyclophosphorothionate (TBPS) binding to the gamma-aminobutyric acid (GABA)-mediated chloride ionophore was carried out in 104 brain areas of entorhinal cortex-kindled and control rats. Subjects were sacrificed either 24 h or 28 days after the last kindled seizure. Kindled subjects in the 24 h group showed reductions in mean [35S]TBPS binding in the lateral nucleus of the amygdala (-31%), the infralimbic cortex (-14%), and the paracentral nucleus of the thalamus (-22%). At 28 days, reductions in binding were observed in the infralimbic cortex (-15%) and the paracentral nucleus of the thalamus (-18%). These data suggest that repeated seizures (kindling) modify the GABA-mediated chloride ionophore, and that in some brain areas related to seizure generalization the modifications are very long lasting.