Objectives:The antagonistic effects of serum with Bu Shen Decoction （BS） on apoptosis of PC12 cells induced by glutamate （Glu） were investigated in vitro. So were the effects of serum with BS on the calcium signal transduction system.Methods:The antagonistic action of the BS on neurotoxicity induced by Glu was observed with MTT method.The fluorescence microscope technique was employed to observe the effect of BS on apoptosis of PC12 cells induced by Glu. Its intracellular free calcium concentration was determined by flow cytometry.The Western-blotting technique was applied for observing the effect of BS on phosphorylation of CaMK Ⅱ in apoptotic PC12 cells.Results:The serum with BS in 20% concentration was discovered to be able to exert antagonistic effect on Glu-induced excitatory neurotoxicity and to inhibit the apoptosis of PC12 cells induced by Glu. Moreover

it was discovered that the increase in intracellular free calcium concentration and the excessive phosphorylation of CaMK Ⅱ during apoptosis of PC12 cells induced by Glu could be inhibited by serum with BS in 20% concentration.Conclusion:BS exert an antagonistic action on excitatory neurotoxicity induced by Glu.The mechanism of neuroprotective effect afforded by serum with BS might be related with relieving calcium overload and adjusting phosphorylation of the key signal molecules in the downstream of calcium ion signal transduction system.