Epileptiform synchronization and GABA(B) receptor antagonism in the juvenile rat hippocampus. J Pharmacol Exp Ther

The GABAB receptor agonist baclofen enhances the epilepti-form activity induced by 4-aminopyridine (4AP) in juvenile rat hippocampal slices. In this study, we used a similar experimen-tal approach (i.e., field potential, intracellular, and [K]o record-ings in the CA3 area of slices obtained from 15–23-day-old rats) to establish whether antagonizing GABAB receptors could exert opposite (presumably anticonvulsant) effects. Bath application of 4AP (50 M) induced spontaneous interictal and ictal dis-charges along with synchronous GABA receptor-mediated po-tentials. All types of 4AP-induced synchronous activity oc-curred more frequently during application of the GABAB receptor antagonist p3-amino-propyl,p-diethoxymethylphos-phonic acid (CGP 35348) (0.1–1 mM; EC50 0.25 mM). More-over, CGP 35348 augmented the frequency and, to a lesse