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目的:探讨衰老过程中脑细胞线粒体和突触体外周型苯二氮卓受体(PBRs)的动态变化以及与外周血血小板膜PBRs相关性的生物学意义。方法:实验动物分为3月龄、12月龄和24月龄3组。动物断头取血后,迅速取脑。采用梯度离心技术提取大脑皮质线粒体和海马突触体,低渗溶血法制备外周血血小板膜。应用放射配基[3H]PK11195结合实验测定PBR结合活力。结果:3组比较,大脑皮质线粒体(F=194.6)、海马突触体(F=94.2)、外周血血小板膜(F=162.2)[3H]PK11195结合活性差异均有显著性(P<0.001)。随着鼠龄增加,上述指标显著下降。外周血血小板膜[3H]PK11195结合活性与大脑皮质线粒体(r=0.894)、海马突触体(r=0.893)[3H]PK11195结合活性比较差异均具有显著性(P<0.001)。结论:大脑皮质线粒体、海马突触体PBRs水平呈增龄下降改变,外周血血小板膜[3H]PK11195结合活性能够反映脑组织该指标的变化。
OBJECTIVE: To investigate the biological significance of the dynamic changes of mitochondria and synaptosomes perinuclear type benzodiazepine receptors (PBRs) in brain cells during aging and their relationship with peripheral blood platelet membrane PBRs. Methods: Experimental animals were divided into 3 months, 12 months and 24 months of age 3 groups. Animals decapitated blood, quickly take the brain. Gradient centrifugation was used to extract mitochondria and hippocampal synaptosomes in the cerebral cortex. Peripheral blood platelet membranes were prepared by hypotonic hemolysis. PBR binding activity was determined using radioligand [3H] PK11195 binding assay. Results: The binding activity of [3H] PK11195 in mitochondria of cerebral cortex (F = 194.6), hippocampal synaptosomes (F = 94.2) and peripheral blood platelets (F = 162.2) . With the increase of age, the above indexes decreased significantly. The binding activity of [3H] PK11195 in peripheral blood platelet membrane was significantly different from that of cortical mitochondria (r = 0.894) and hippocampal synaptosomes (r = 0.893) [3H] PK11195 (P <0.001). CONCLUSION: PBRs of mitochondria and hippocampal synaptosomes in the cerebral cortex change with age. The binding activity of platelet membrane [3H] PK11195 in peripheral blood can reflect the change of this index in brain tissue.