EXCITOTOXIC INCREASE OF XANTHINE DEHYDROGENASE AND XANTHINE-OXIDASE IN THE RAT OLFACTORY CORTEX

Excitotoxic lesions induced by systemic injection of kainic acid, resu lted in 2-3-fold increase of xanthine dehydrogenase and xanthine oxida se activities in the rat olfactory cortex 48-72 h after drug administr ation. A significant increase of the xanthine oxidase/dehydrogenase ra tio was also observed at 4 and 48 h post-injection. No similar changes were noticed in the hippocampus. The enhancement of enzyme activity s eems to be primarily a consequence of the altered cell composition in damaged area. Free radicals produced by the increased oxygen-dependent form of the enzyme could in turn aggravate the excitotoxic brain inju ry.