CARBAMAZEPINE-INDUCED BLOCKADE OF INDUCTION OF LONG-TERM POTENTIATIONIN THE PERFORANT PATH-DENTATE GYRUS PATHWAY IN CHRONICALLY PREPARED RABBITS

We investigated the effects of a representative anti-epileptic or anti -psychotic drug, carbamazepine (CBZ), on the induction of long-term po tentiation (LTP) in the perforant path-dentate gyrus pathway in 15 chr onically prepared rabbits. Pharmacokinetically injected low-dose CBZ, which produced steady serum levels of 2.2-3.3 mu g/ml (mean +/- S.D. 2 .85 +/- 0.40), variably affected the induction of LTP, blocking it or showing almost no effect. The high-dose CBZ, which produced steady ser um levels of 6.5-8.6 mu g/ml (8.01 +/- 0.87), always blocked the induc tion of LTP. These results indicate that CBZ dose-dependently blocks t he induction of LTP. The possible mechanisms underlying this blockade are discussed, especially in association with the possible inhibitory action of CBZ on N-methyl-D-aspartate (NMDA) receptors.