Kynurenines and Seizures

TLDR

Kynurenines, neuroactive tryptophan metabolites, are known to provoke seizures in rodents and amphibians, synergize with strychnine, and have their effects modulated by GABA derivatives and standard anticonvulsants. The study aims to determine whether brain kynurenines contribute to the development of epileptic seizures. In mice, administration of l‑ and d,l‑kynurenine induces myoclonic hind‑leg seizures. The convulsant action of l‑kynurenine is blocked by taurine, partially inhibited by l‑glycine, and unaffected by GABA or muscimol.

Abstract

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.