title: [Potent convulsant effects of a benzodiazepine inverse agonist, methyl beta-carboline-3-carboxylate in cats].
abstract: The convulsant properties of methyl beta-carboline-3-carboxylate (beta-CCM), which is a homologue of a putative benzodiazepine receptor ligand in the mammalian central nervous system, were examined in cats. Subcutaneous injection of 0.5 mg/kg of the beta-CCM produced various degrees of myoclonic jerks always accompanied by cortical spike burst. Some autonomic symptoms such as tachypnea, hypersecretion of thick mucous saliva, vomiting and mydriasis were also presented. Subcutaneous injection of 1.0 mg/kg of the compound induced a generalized tonic-clonic convulsion. Injection of the same amount of the drug 1 hour later in the same cats failed to provoke a generalized seizure. Repeated injection of the same dose 3 hours later provoked a generalized seizure, but with a longer latency. However, repetition of the experiments 24 hours after or 10 days after the first injection consistently induced the same type of generalized seizure with the same latency as the first injections. These results support the suggestion that the pharmacological effect, especially the convulsive effect, of beta-CCM is dose-related, reversible and reproducible in the same cats and among different cats. Moreover, the postictal refractory period in this model of epilepsy may continue about for 3 hours.
mesh_terms: D000818:Animals; D001569:Benzodiazepines / Q000037:antagonists & inhibitors*; D002243:Carbolines / Q000494:pharmacology*; D002415:Cats; D002540:Cerebral Cortex / Q000503:physiopathology; D004305:Dose-Response Relationship, Drug; D004569:Electroencephalography; D004576:Electromyography; D007211:Indoles / Q000494:pharmacology*; D012640:Seizures / Q000139:chemically induced* / Q000503:physiopathology
chemical_list: D002243:Carbolines; D007211:Indoles; D001569:Benzodiazepines; C026072:1-methyl-beta-carboline-3-carboxylic acid