Kynurenines and seizures.

Recent data and concepts concerning the convulsant effects of kynurenines, neuroactive metabolites of tryptophan, in mice, rats, and frogs are reviewed. Myoclonic seizures of the hindlegs are induced in mice by l- and d,l-kynurenine. Both l- and d,l-kynurenine exhibit a selective synergism with strychnine. The convulsant effect of l-kynurenine is selectively antagonized by taurine, less selectively by l-glycine, and not at all by gamma-aminobutyric acid (GABA) or the GABA agonist muscimol. Derivatives of GABA and some standard anticonvulsant drugs alter seizures induced by l-kynurenine and quinolinic acid in different ways. The involvement of brian kynurenines in the genesis of epileptic seizures is suggested.