Acute ammonia treatment in vitro and in vivo inhibits the synthesis of a neuroprotectant kynurenic acid in rat cerebral cortical slices

Abstract

The synthesis of kynurenic acid (KYNA) from kynurenine was measured in the cerebral cortical slices. In vitro, ammonium acetate at the subtoxic to toxic concentration range from 1 mM to 10 mM dose-dependently inhibited KYNA synthesis (IC50=2.99 mM). Ammonia treatment in vivo decreased KYNA synthesis by 30%. These results suggest that impaired neuroprotection exerted by KYNA might be a potential contributor to the glutamate receptor-mediated aspect of acute ammonia neurotoxicity.