ACUTE AMMONIA TREATMENT IN-VITRO AND IN-VIVO INHIBITS THE SYNTHESIS OF A NEUROPROTECTANT KYNURENIC ACID IN RAT CEREBRAL CORTICAL SLICES

The synthesis of kynurenic acid (KYNA) from kynurenine was measured in the cerebral cortical slices. In vitro, ammonium acetate at the subto xic to toxic concentration range from I mM to 10 mM dose-dependently i nhibited KYNA synthesis (IC50 = 2.99 mM). Ammonia treatment in vivo de creased KYNA synthesis by 30%. These results suggest that impaired neu roprotection exerted by KYNA might be a potential contributor to the g lutamate receptor-mediated aspect of acute ammonia neurotoxicity. (C) 1998 Elsevier Science B.V.