DELAYED APPLICATION OF AURINTRICARBOXYLIC ACID REDUCES GLUTAMATE-INDUCED CORTICAL NEURONAL INJURY

The non-specific endonuclease inhibitor, aurintricarboxylic acid (ATA) , attenuated glutamate-induced destruction of cultured cortical neuron s. In part, this protective effect likely reflected the ability of ATA to produce a slowly developing block of N-methyl-D-aspartate receptor -mediated inward whole cell current or increase in intracellular free Ca2+. However, ATA also attenuated a high K+-induced increase in intra cellular free Ca2+ in the presence of D-aminophosphonovalerate, sugges ting that ATA may have a more general effect on Ca2+ homeostasis. In a ddition, ATA attenuated glutamate neurotoxicity even if added up to 2 hr after completion of glutamate exposure, a time when glutamate antag onists or lipid peroxidation inhibitors are no longer neuroprotective. Involvement of apoptosis in this excitotoxic death is unlikely, as So uthern blotting of genomic DNA revealed no evidence of fragmentation, and death was not prevented by inhibitors of RNA or protein synthesis. Most likely, ATA interferes with some key downstream consequences of excitotoxic glutamate receptor overactivation. (C) 1994 Wiley-Liss, In c.