The interaction of the beta-carboline derivative DMCM with inhibitory amino acid responses on cultured mouse neurones.

Benzodiazepine (BZ) and GABA receptors are associated in the neuronal membrane. GABA responses are enhanced in the presence of BZs. The convulsant DMCM (methyl 6,7-dimethoxy-4-ethyl-beta-carboline-3-carboxylate), like other beta-carbolines, binds with high affinity to BZ receptors. The effects of DMCM and of the BZ midazolam, on GABA responses, were studied in mouse cultured neurones using intracellular recording techniques. GABA responses were usually reduced by DMCM and potentiated by midazolam. This, with an occasional direct facilitatory effect on the membrane, is consistent with the convulsive action of DMCM.