title: Bidirectional effects of beta-carbolines in reflex epilepsy.
abstract: Derivatives of ethyl-beta-carboline-3-carboxylate, ZK 91296, ZK 93423 and ZK 95962 have potent anticonvulsant activity against sound-induced seizures in audiogenic DBA/2 mice and against photically-induced seizures in the baboon, Papio papio. The convulsant beta-carbolines, DMCM and beta-CCM, have proconvulsant and convulsant activity in the same animal models. DMCM and beta-CCM are similar in potency as convulsants in DBA/2 mice (ED50 value for DMCM: 1.3 mg/kg; ED50 value for beta-CCM; 0.8 mg/kg), but differ with respect to their profiles for protection by anticonvulsant drugs. The anticonvulsant potencies of diazepam and clobazam are similar against both types of beta-carboline-induced seizures, whereas quazepam protects better against beta-CCM seizures (4 fold elevation in ED50 value at 1 mg/kg quazepam IP) than against DMCM seizures (1.7 fold elevation in ED50 value), supporting a preferential action of beta-CCM on BZ1 receptors. Valproate (400 mg/kg) and gamma-vinyl-GABA (1.5 g/kg) protect better against beta-CCM seizures (9.5 and 5.9 fold elevations in ED50 values respectively) than against DMCM seizures (1.8 and 2.7 fold elevations in ED50 values respectively). The excitatory amino acid antagonist, 2-amino-7-phosphonoheptanoic acid, has significant anticonvulsant activity against DMCM seizures. The elevated regional GABA levels in brains of DBA/2 mice observed during beta-CCM seizures are eliminated by the pretreatment with Ro 15-1788, which also blocks the seizure activity.
mesh_terms: D000818:Animals; D000927:Anticonvulsants / Q000009:adverse effects / Q000627:therapeutic use*; D001921:Brain / Q000187:drug effects / Q000378:metabolism / Q000503:physiopathology; D002243:Carbolines / Q000009:adverse effects / Q000627:therapeutic use*; D004827:Epilepsy / Q000139:chemically induced / Q000188:drug therapy*; D005260:Female; D008297:Male; D051379:Mice; D008811:Mice, Inbred DBA; D010215:Papio; D014635:Valproic Acid / Q000627:therapeutic use; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
chemical_list: D000927:Anticonvulsants; D002243:Carbolines; C034818:methyl 6,7-dimethoxy-4-ethyl-beta-carboline-3-carboxylate; D005680:gamma-Aminobutyric Acid; D014635:Valproic Acid; C036150:beta-carboline-3-carboxylic acid methyl ester