Regional distribution of tyrosine, tryptophan, and their metabolites in the brain of epileptic El mice.

Tyrosine, tryptophan, and their metabolites in the brain of ddY, non-stimulated El (El (-)), and stimulated El (El (+)) mice were measured using the three dimensional HPLC. The tryptophan content was lower in El (+) than ddY and El (-) mice. The 5-hydroxytryptophan content was much higher in both El groups. The serotonin content of El (+) was higher than that of ddY and El (-) mice. The kynurenine content was remarkably high in the El mice. The dopamine content was lower in El (-) than in ddY mice, whereas it was greater in El (+) than in El (-) mice. The norepinephrine showed higher levels in El (+) mice. These facts suggest that El mice possess congenital metabolic abnormalities of tryptophan and tyrosine and that kynurenine may play an important role as convulsant in El mice seizures along with changes in serotonin, dopamine, and norepinephrine that are inhibitory agents and responded to the repetitive convulsions.