3-HYDROXYKYNURENINE TOXICITY ON THE RAT STRIATUM IN-VIVO

3-Hydroxykynurenine (3-HK) is a tryptophan metabolite whose level in t he brain is elevated under several pathological states including Hunti ngton's disease. In the present study, we examined the possible toxici ty of 3-HK by injection of this substance into rat brain. Intrastriata l injection of 3-HK (50 nmol) induced tissue damage around the injecte d site. Quinolinic acid (QA) at 200 nmol also induced tissue damage, w hich was comparable in size to that induced by 50 nmol 3-HK. Co-admini stration of MK-801 significantly reduced QA-induced lesion, but failed to prevent 3-HK-induced lesion. On the other hand, the antioxidant N- acetyl-L-cysteine (10 nmol) reduced 3-HK-induced damage. Thus, 3-HK ma y be involved in brain pathogenesis by providing oxygen radicals.