Flow-cytometric analysis on kainate-induced decrease in the cellular content of non-protein thiols in dissociated rat brain neurons

Abstract

In order to study the kainate-induced oxidative stress on brain neurons, the effect of kainate on cellular content of glutathione in rat cerebellar neurons were examined using a flow cytometer and 5-chloromethylfluorescein, a fluorescent dye for cellular non-protein thiols (mainly glutathione). Kainate at concentrations ranging from 30 μM to 1 mM produced a dose-dependent decrease in cellular content of glutathione. Exposure of neurons to kainate at concentrations of 300 μM or greater seemed to deplete cellular glutathione. Potency of kainate in reducing cellular content of glutathione was greater than those of glutamate and N-methyl- d-aspartate (NMDA). Kainate-induced decrease in cellular content of glutathione was partly attenuated by 6-nitro-7-cyano-quinoxaline-2,3-dione, a blocker of non-NMDA receptors and removal of external Ca 2+. Results indicate that kainate causes Ca 2+-dependent oxidative stress that decreases the cellular content of glutathione via activation of non-NMDA type of glutamate receptors.