Inhibitory effects of constituents of Gastrodia elata Bl. on glutamate-induced apoptosis in IMR-32 human neuroblastoma cells

The inhibitory effects of the constituents of Gastrodia elata BI. (GE) on g lutamate-induced apoptosis in human neuronal cells were investigated using lh IMR32 human neuroblastoma cells. Glutamate (GLU) induced DNA Fragmentati on, a hallmark of apoptosis, in a dose-dependent manner. GLU also induced a slow and sustained increase in intracellular Ca2+ concentration. Treatment with EGTA, an extracellular Ca2+ chelator, in a nominal Ca2+-free buffer s olution abolished the GLU-induced intracellular Ca2+ increase, indicating t hat GLU stimulated Ca2+ influx pathway in the IMR32 cells. BAPTA, atl intra cellular Ca2+ chelator, significantly inhibited the GLU-induced apoptosis a ssessed by the flow cytometry measuring hypodiploid DNA content indicative of apoptosis, implying that intracellular Ca2+ rise may mediate the apoptot ic action of GLU. Vanillin (VAN) and p-hydroxybenzaldehyde(p-HB), known con stituents of GE, significantly inhibited both intracellular Ca2+ rise and a poptosis induced by GLU. These results suggest that the apoptosis-inhibitor y actions of the constituents of GE may account, at least in part, for the basis of their antiepileptic activities. These results further suggest that intracellular Ca2+ signaling pathway may be a molecular target of the cons tituents of GE.