Abstract: Recently,the intracelluar free calcium overload has been considered as an impor- tant factor in development of ischemic brain damage.In this paper,the effect of AMG-1 on free calcium concentration(Ca²⁺i)in rat intrasynaptosome and on the isolated rat tail artery contraction induced by norepinephrine(NE)were studied by using Fura- 2 fluorescence technique and contraction force measurement,respectively.The　results show that:AGM-1 10 μmol·L^-1 and 100 μmol·L^-1 reduced the KCl induced Ca²⁺i increase by 19±11% and 57±12%.2.AMG-1 100 μmol·L^-1 markedly decreased the NE-dependent intracellular calcium induced contraction force(43 ±11%).In our previous study,AMG-1 was shown to have improving effect on ischemic damage following middle cerebral artery occlusion in rats.On the basis of these results,we suggest that the mechanism of AMG-1 in improving cerebral ischemic damage may be due to the decrease ofCa²⁺i.