Abstract: To explore the neuroprotective effects of gypenoside(GP) on glutamateinduced cytotoxicity to cortical neurons and investigate its signaling pathway. Methods: The oxidative neurotoxicity model was constructed in primary cortical neurons isolated from Wistar rat E13～14 embryos following a high dose glutamate to the neurons directly. GP was added before the damage. The viability of cells after various treatments was detected by MTT method. Ho33342 and PI double labeled method was used to analyse cellular death pathways. The contents of NO and H2O2 were detected. The changes of mitochondria membrane potential of neurons were analyzed by flow cytometry.Results: Glutamate triggered two cellular death pathways:

Key words: Gynostemma, Glutamic acid, Neurons, Oxidative neurotoxicity