The Study Of Gypenosides Protecting Immature Primary Cortical Neurons From Oxidative Toxicity Induced By Glutamate

Background: At present, glutamate is known to be a potent neurotoxin when presents in excess at synapses. Both glutamate excitotoxicity mediated by ion-glutamate receptors and oxidative toxicity via the inhibition of glutamate/cystine antiporter have been shown to contribute to neural degeneration diseases. However the pathogenesis of oxidative toxicity induced by glutamate is not fully understood. Gynostemma Pentaphyllum (Thunb) Makino is a widespread herb in South China. The molecular components responsible for it's actions are gypenosides(GP).Within more than 80 different gypenosides, the basic structures of 6 gypenosides are similar with ginsenosides. In general, GP have a number of pharmacological actions in different body systems including inhibiting carcinoma, improving memory in experimental animals as well as anti-aging, anti-oxidative stress etc. SH-6, one kind of gypenosides is correlated with enhancing performance in a behavioral memory test. Although GP protective actions have been reported on the nervous system either in vivo or in vitro, the mechanism involved in the protective effects of GP on glutamate-induced oxidative toxicity remains to be established.Objective: Neural degeneration in acute conditions such as stroke, epilepsy, trauma, hypoxia and hypoglycemia and chronic neurodegenerative diseases such as Alzheimer's, Parkinson's and Huntington's diseases and amyotrophic lateral sclerosis have been proved to be related to glutamate neurotoxicity. We therefore tested the oxidative toxic effect of glutamate on rat cortical neurons in primary cultures and the neuroprotective potential of GP. Furthermore, we also analyzed the signal pathway...