Summary： Adult-bom neurons undergo a transient period of plasticity during their integration into the neural circuit. This transient plasticity may involve NMDA receptors containing NR2B, the major sub unit expressed...Summary： Adult-bom neurons undergo a transient period of plasticity during their integration into the neural circuit. This transient plasticity may involve NMDA receptors containing NR2B, the major sub unit expressed at early developmental stages. The main objective of the present study was to investigate the effects of NR2B gene knockdown on the functional integration of the adult-born granule cells gen- erated from the subgranule zone （SGZ） in the hippocampus. The small interfering RNA （siRNA） was used to knock down the NR2B gene in the adult-born hippocampal neurons. In the functional integration test, the mice were exposed to a novel environment （open field arena）, and the expression of c-fos was immunohistochemically detected in the hippocampus. After exposure to the novel environment, siRNA-NR2B mice were significantly different from control mice in either the number of squares or the number of rears they crossed, showing decreased horizontal and vertical activity （P〈0.05）. Moreover, the c-fos expression was increased in both control and siRNA-NR2B mice after open field test. But, it was significantly lower in siRNA-NR2B neurons than in control neurons. It was concluded that the neu- ral activity of newborn neurons is regulated by their own NR2B-containing NMDA glutamate receptors during a short, critical period after neuronal birth.展开更多
目的:检测洛伐他汀(lovastatin,LOV)对N⁃甲基⁃D⁃天门冬氨酸(N⁃methyl⁃D⁃aspartate,NMDA)诱导的兴奋性毒性的神经保护作用并探讨LOV调节NMDA受体功能在神经保护中的潜在机制。方法:培养的大鼠原代神经元细胞分未处理组、LOV组、NMDA组、L...目的:检测洛伐他汀(lovastatin,LOV)对N⁃甲基⁃D⁃天门冬氨酸(N⁃methyl⁃D⁃aspartate,NMDA)诱导的兴奋性毒性的神经保护作用并探讨LOV调节NMDA受体功能在神经保护中的潜在机制。方法:培养的大鼠原代神经元细胞分未处理组、LOV组、NMDA组、LOV+NMDA组、谷氨酸(glutamate,Glu)组及Glu+APV(一种特异性NMDA受体拮抗剂)组。免疫荧光染色检测神经元形态,TUNEL分析检测神经元凋亡,免疫印迹测定蛋白水平,生物素化法检测细胞表面受体。结果:①与NMDA组或Glu组少数幸存微管相关蛋白(microtubule⁃associated protein 2,MAP⁃2)阳性神经元相比,LOV+NMDA组和Glu+APV组MAP⁃2阳性神经元的数量明显增多,神经元树突的数目和长度均明显增加(P<0.001);②与NMDA组或Glu组TUNEL阳性细胞显著增多相比,LOV+NMDA组或Glu+APV组TUNEL阳性细胞显著减少(P<0.001);③与未处理组相比,NMDA组NMDA受体蛋白(N⁃methyl⁃D⁃aspartate receptor,NR2B)表达显著减少(P<0.001),而LOV预处理后增加NR2B蛋白表达(P<0.05);④生物素化法检测细胞表面受体显示,NMDA处理导致细胞表面大部分NR2B丢失(P<0.001),LOV预处理能显著减少NMDA诱导的细胞表面NR2B丢失(P<0.05)。进一步研究显示,NMDA处理后,NR2B在酪氨酸(tyrosine,Tyr)1472位点的磷酸化下降(P<0.05),LOV预处理显著恢复Tyr1472位点的磷酸化(P<0.05)。结论:LOV能减轻NMDA诱导的兴奋性毒性损害,这一作用可能与其影响NMDA受体亚单位NR2B的细胞内吞和/或胞内降解,进而调节NR2B表面分布有关。展开更多
基金supported by the National Natural Science Foundation of China(No.81000537)
文摘Summary： Adult-bom neurons undergo a transient period of plasticity during their integration into the neural circuit. This transient plasticity may involve NMDA receptors containing NR2B, the major sub unit expressed at early developmental stages. The main objective of the present study was to investigate the effects of NR2B gene knockdown on the functional integration of the adult-born granule cells gen- erated from the subgranule zone （SGZ） in the hippocampus. The small interfering RNA （siRNA） was used to knock down the NR2B gene in the adult-born hippocampal neurons. In the functional integration test, the mice were exposed to a novel environment （open field arena）, and the expression of c-fos was immunohistochemically detected in the hippocampus. After exposure to the novel environment, siRNA-NR2B mice were significantly different from control mice in either the number of squares or the number of rears they crossed, showing decreased horizontal and vertical activity （P〈0.05）. Moreover, the c-fos expression was increased in both control and siRNA-NR2B mice after open field test. But, it was significantly lower in siRNA-NR2B neurons than in control neurons. It was concluded that the neu- ral activity of newborn neurons is regulated by their own NR2B-containing NMDA glutamate receptors during a short, critical period after neuronal birth.
文摘目的:检测洛伐他汀(lovastatin,LOV)对N⁃甲基⁃D⁃天门冬氨酸(N⁃methyl⁃D⁃aspartate,NMDA)诱导的兴奋性毒性的神经保护作用并探讨LOV调节NMDA受体功能在神经保护中的潜在机制。方法:培养的大鼠原代神经元细胞分未处理组、LOV组、NMDA组、LOV+NMDA组、谷氨酸(glutamate,Glu)组及Glu+APV(一种特异性NMDA受体拮抗剂)组。免疫荧光染色检测神经元形态,TUNEL分析检测神经元凋亡,免疫印迹测定蛋白水平,生物素化法检测细胞表面受体。结果:①与NMDA组或Glu组少数幸存微管相关蛋白(microtubule⁃associated protein 2,MAP⁃2)阳性神经元相比,LOV+NMDA组和Glu+APV组MAP⁃2阳性神经元的数量明显增多,神经元树突的数目和长度均明显增加(P<0.001);②与NMDA组或Glu组TUNEL阳性细胞显著增多相比,LOV+NMDA组或Glu+APV组TUNEL阳性细胞显著减少(P<0.001);③与未处理组相比,NMDA组NMDA受体蛋白(N⁃methyl⁃D⁃aspartate receptor,NR2B)表达显著减少(P<0.001),而LOV预处理后增加NR2B蛋白表达(P<0.05);④生物素化法检测细胞表面受体显示,NMDA处理导致细胞表面大部分NR2B丢失(P<0.001),LOV预处理能显著减少NMDA诱导的细胞表面NR2B丢失(P<0.05)。进一步研究显示,NMDA处理后,NR2B在酪氨酸(tyrosine,Tyr)1472位点的磷酸化下降(P<0.05),LOV预处理显著恢复Tyr1472位点的磷酸化(P<0.05)。结论:LOV能减轻NMDA诱导的兴奋性毒性损害,这一作用可能与其影响NMDA受体亚单位NR2B的细胞内吞和/或胞内降解,进而调节NR2B表面分布有关。
