脑缺血再灌注神经细胞血小板活化因子受体蛋白特性研究  

Study on the characteristics of platelet-activating factor receptor protein during focal reversible ischemia in rat cerebral cortex

作　　者：张雄 袁成林 张桁忠 许俊 林健雯[2] 黄如训[2] 

机构地区：[1]扬州大学临床医学院神经科,225001 [2]中山大学附属第一医院神经科

出　　处：《中华核医学杂志》2004年第3期178-180,共3页Chinese Journal of Nuclear Medicine

基　　金：江苏省社会发展计划科技基金资助项目 (BS2 0 0 2 0 2 1 )

摘　　要：目的　探讨大鼠局灶性脑缺血再灌注后血小板活化因子 (PAF)受体特性的变化。方法建立一侧大脑中动脉线栓闭塞再通模型 ,超速离心制备缺血脑皮质神经细胞突触膜和微粒体。采用放射配基结合实验 ,检测脑缺血再灌注后PAF受体的平衡解离常数 (Kd)和最大结合数量 (Bmax)。结果　Scatchard作图分析显示 ,各组样本均存在 3个特异性PAF结合位点 ,其中 2个位于微粒体 ,另 1个在突触膜上。单纯缺血 90min时 ,突触膜位点Kd 和Bmax明显减小 ;再灌注 1d后 ,微粒体上 2个位点的Kd、Bmax明显下降 ,至 7d均未恢复到假手术组水平。结论　缺血再灌注可诱导脑皮质神经细胞PAF受体下调 ,胞内受体下调晚发于突触膜受体。Objective To investigate the characteristic alteration of specific binding sites for 3H-platelet-activating factor (PAF) in subcellular fractions of rat cerebral cortex during ischemia/reperfusion. Methods Mature Wistar rats were randomly divided into six groups: sham-operated conrtol group, simple ischemia group, and 6 h, 1 d, 4 d, 7 d reperfusion groups. The right middle cerebral artery occlusion was lasted for 90 min, and then reperfusion was allowed for different time periods before decapitation. In sham-operated control rats, the occluding thread was inserted only <9 mm instead of 23 mm in real operated groups. The existence and characteristic alteration of specific binding sites for PAF in rat cortex were measured by 3H-PAF radioligand binding assay. Results Scatchard analysis showed three specific binding sites in subcellular fractions of rat cerebral cortex. Of the two binding sites found in the microsome fraction, one showed the highest affinity. The third binding site was present in the synaptic membrane fraction. After focal cerebral ischemic-reperfusion, the B_ max and K_d of binding site in the synaptic membrane progressively decreased, so did the two binding sites in the microsome fraction reperfused 1 d later compared with the sham-operated control group. Conclusion These results indicate that PAF receptor protein was subjected to down-regulation both in the microsome fraction and synaptic membrane fraction, and the former was down-regulated later.

关 键 词：脑缺血 血小板活化因子受体 放射配位体测定 大鼠 

分 类 号：R741[医药卫生—神经病学与精神病学]