急性脑缺血谷氨酸受体的变化特征

Characteristics of changes of glutamate receptors in the brain during acute cerebral ischemia in rats

目的：观察脑缺血再灌流过程中缺血灶和下丘脑的谷氨酸受体的变化特征。方法：应用高效液相色谱仪，受体的放射配体结合分析分别监测大脑中动脉阻塞再灌流大鼠缺血灶和下丘脑的谷氨酸（Ｇｌｕ）含量，ＧｌｕＲ容量及离解常数Ｋｄ变化。结果：缺血及再灌流全过程中，缺血灶的ＧｌｕＲ及其亲合力持续降低，而下丘脑呈现两次大幅度起伏变化，两部位Ｇｌｕ含量与ＧｌｕＲ容量均呈显著负相关（ｒ分别为－０．２３３和－０．３８５，Ｐ分别＜０．０５和０．００１）。结论：缺血早期缺血灶的ＧｌｕＲ有敏感的生物学活性，早期阻滞其ＧｌｕＲ对缺血性脑损伤有重要干预意义；缺血及再灌流全过程中，下丘脑的ＧｌｕＲ始终具有敏感的生物学活性，干预其ＧｌｕＲ对减轻缺血性应激性脑损伤有重要价值。

Objective: To observe the characteristics of changes of glutamate (Glu) receptors in ischemic foci and the hypothalamus during cerebral ischemia/reperfusion. Methods: After the middle cerebral artery was occluded and reperfused in rats, the changes of the Glu content and GluR capacity and its Kd in the ischemic foci and the hypothalamus were observed with radiolegend binding assay and highperformance liquid chromatography. Results: In the whole course of the acute cerebral ischemia/reperfusion, GluR capacity and affinity were continuously decreased. Glu content and GluR capacity in the ischemic foci were negatively correlated with those in the hypothalamus (r=-0.233 and -0.385, P<0.05 and 0.001). Conclusion: In the early stage of ischemia, GluR in the ischemic foci is biologically sensitive, which suggests that the blocking of GluR in the early stage of ischemia is very important for reducing ischemic damage in the brain. GluR in the hypothalamus exhibits persistent sensitive biological activity during the whole course of ischemia/reperfusion. Therefore, blocking of GluR is also of important value for reducing ischemic stress reactioninduced brain damage.