Proconvulsant effects in baboons of beta-carboline, a putative endogenous ligand for benzodiazepine receptors.

beta-Carboline-3-carboxylic acid ethyl ester (beta-CCE) was tested on two models of epilepsy in the baboon: kainic acid-induced limbic status epilepticus and photosensitive epilepsy. Beta-CCE, at very low doses ranging from 8 to 100 microgram/kg (i.v.), induced a reactivation of the limbic focus and photomyoclonic and generalized seizures in photosensitive and non-photosensitive baboons. The proconvulsant effect of beta-CCE may be associated with its binding to a particular subclass of benzodiazepine receptors.