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

Conflicting data exist concerning the interaction of carbamazepine (CBZ) and GABA-receptors involved in the pathophysiology of neuropsychiatric disorders. 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 microM (ca. 10-30 fold the therapeutic level, tested up to 90 min). Therefore, therapeutic effects of CBZ cannot be due to acute modulations of postsynaptic GABA-responses.