Kainic Acid, NMDA and Bicuculline Induce Elevation in Concentrations of Glutathione and Amino Acids <i>in Vivo</i>: Biomarkers for Seizure Predisposition?

Abstract

The present study was carried out to investigate the effect of NMDA, bicuculline and kainic acid (KA) on the extracellular concentration of glutathione, phosphoethanolamine (PEA) and taurine in rat hippocampus in vivo . Rats were implanted with intrahippocampal microelectrodes perfused with free-glucose Krebs-Ringer solution and allowed to recover for about 2 h. After assaying baseline concentrations of amino acids, NMDA or bicuculline was administered intrahippocampally, whereas KA was given systemically. Either treatment resulted in significant high extracellular concentrations of glutathione, but only NMDA or KA resulted in high concentrations of PEA and taurine. Interestingly, the increase in glutathione concentration due to KA was followed by a delayed increase of glutamate and PEA. Our results demonstrated that increased efflux of glutathione, a common consequence of different neuroexcitotoxic agents, occurs in vivo . Given that the agents used in the present study were also convulsunts, the implication of the findings on seizure predisposition was also considered.