Abstract: Aim The protective Effect and mechanismof TPG on PC 12 cells in calcium overloading injury models werestudied.Methods Two injury models induced by KCl and NMDA wereused to assay the action of TPG in cultured PC 12 cells.Results The morphological examination revealed that TPG possessed obvious protective effects on PC12 cells in injury models.MT T and LDH measurementindicated that TPG increased the numberof live cells and reduced the extent of cell injury significantly.TPG alsolessened the concentration of calcium ion in cytoplasm.Conclusion T PG protected rat PC 12 cells against twocalcium overloading injuries Effectively in vitro.I ts actions may deal with anti oxidation, inhibition of NO production and blocking of bothty pes of calcium channel.

Key words: total paenony glycoside(TPG), PC 12 cell, calcium overload, KCl, NMDA