AUGMENTATION OF GABA-B INDUCED FIELD POTENTIAL CHANGES BY CARBAMAZEPINE IN THE HIPPOCAMPUS

The action of systemically administered carbamazepine on GABA induced field potential changes (EFP) in CA1 and CA3 areas of the hippocampal slice preparation of guineapigs was investigated. The total GABA respo nse was increased by extracellular administration of 100 mu mol/l carb amazepine (CBZ) in the mean to 9.4% of the initial value. EFP elicited by the GABA-A agonist muscimol were unaffected. EFP induced by the GA BA-B agonist baclofen were augmented in the mean to 17.9% of the initi al value. The most likely explanation of these results is an agonistic action of CBZ on GABA-B receptors. It is concluded that the antiepile ptic drug carbamazepine, which is used in psychiatry also for the trea tment of mania, may exert its effect via GABA-B receptors. (C) 1997 El sevier Science Inc.