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目的探讨衰老过程大鼠脑组织线粒体和突触体外周型苯二氮受体(PBRs)的动态变化。方法雌性SD大鼠分为乳鼠组、3、12、15、18、24和30月龄组。动物断头后迅速取脑,采用梯度离心法提取大脑皮质线粒体和海马突触体,应用放射配基结合实验测定PBRs结合活力。结果7组比较,皮质线粒体和海马突触体PBRs结合活性差异显著(均P<0.05～0.001)。15月龄以前皮质线粒体和海马突触体PBRs结合活性逐渐下降(P<0.01),15～24月龄PBRs结合活性有下降趋势,但变化不显著(P>0.05)。30月龄组皮质线粒体和海马突触体PBRs结合活性显著高于3月龄组(P<0.01),低于乳鼠组(P<0.05)。结论大脑皮质线粒体、海马突触体PBRs结合活性呈明显增龄性改变,PBRs参与了脑老化过程。
Objective To explore the dynamic changes of peripheral benzodiazepine receptors (PBRs) in the mitochondria and synaptosomes of aging rats. Methods Female Sprague Dawley rats were divided into 3 groups: 3, 12, 15, 18, 24 and 30 months old. Animals were rapidly sacrificed after decapitation. Gradient centrifugation was used to extract mitochondria and hippocampal synaptosomes. Radioligand binding assay was used to determine the binding activity of PBRs. Results There were significant differences in PBRs binding activity between cortical mitochondria and hippocampal synaptosomes in the 7 groups (all P <0.05 ~ 0.001). The binding activity of PBRs in cortex mitochondria and hippocampal synaptosomes decreased gradually (P <0.01) before 15 months of age. The binding activity of PBRs in 15 ~ 24 months old had a decreasing trend, but the change was insignificant (P> 0.05). The PBRs binding activity of cortex mitochondria and hippocampal synaptosome in 30-month-old group was significantly higher than that in 3-month-old group (P <0.01) and lower than that in the suckling group (P <0.05). Conclusions The binding activity of PBRs in mitochondria and hippocampal synaptosomes in the cerebral cortex is obviously aging, and PBRs are involved in the process of brain aging.