Missing action of carbamazepine on postsynaptic GABA-responses of hippocampal CA3-neurons (slice, guinea pig)

Conflicting data exist concerning the interaction of carbamazepine (CBZ) an d GABA-receptors involved in the pathophysiology of neuropsychiatric disord ers. The present study reveals that CBZ failed to alter membrane potential fluctuations mediated by an activation of postsynaptic GABA(A)- and GABA(B) -receptors of hippocampal CA3-neurons even at a bath concentration of 500 m u M (ca. 10-30 fold the therapeutic level, tested up to 90 min). Therefore, therapeutic effects of CBZ cannot be due to acute modulations of postsynap tic GABA-responses. (C) 1998 Elsevier Science B.V./ECNP. All rights reserve d.