高血糖对大鼠局灶性脑缺血细胞外钙离子的影响

Effect of Hyperglycemia on Extracellular Calcium Activity Following Focal Cerebral Ischemia in Rats

应用钙离子选择性微电极测定血糖对大鼠局灶性脑缺血后细胞外钙离子浓度的影响。结果发现正常血糖组（n＝8）和高血糖组（n＝8）在缺血早期已发生细胞外钙离子浓度下降（P＜0．01），而缺血15～30min时高血糖组较正常血糖组下降更为显著（P＜0．05）。提示高血糖加重脑缺血损伤可能与加强细胞外钙离子内流有关。

In the present study, we detected changes of extracellular calcium activity before and after middle cerebral aYtery occlusion in hyperglycemic and normoglycemic rats. We found that preischemic extra cellular calcium activity of both groups were similar. During 3- 14 minutes post - ischemia, the extracellular calcium activity of both groups declined sharply. Compared with pre - ischemia the results were statistically significant (P<0.01). The decline of the extracellular calcium activity in both groups was continous and slow during 15 - 30 minutes post- ischemia, but that of the hyperglycemic rats was more marked than the normoglycemic(P<0.05). This finding strongly suggests that hyperglycemia can exacerbate brain damage, which is associated with augmenting extracellular calcitun influx.