[Effect of AMG-1 on free intrasynaptosome calcium level and on the isolated artery contraction induced by norepinephrine].

Recently, the intracellular free calcium overload has been considered as an important factor in the 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: 1. AMG-1 10 mumol.L-1 and 100 mumol.L-1 reduced the KCl induced [Ca2+]i increase by 19 +/- 11% and 57 +/- 12%. 2. AMG-1 100 mumol.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 of [Ca2+]i.