Li Liao-Liao, Sun Li-Na, Zhou Hong-Yi, Li Zheng-Bin, Wang Xiao-Liang
Department of Pharmacology, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
Neurosci Lett. 2006 Sep 1;404(3):249-53. doi: 10.1016/j.neulet.2006.06.003. Epub 2006 Jun 27.
The Na+/Ca2+ exchanger (NCX) is an antiporter located in the plasma membrane of many cells, which can maintain the intracellular Ca(2+) homeostasis. Some studies have shown the close relationship of NCX and cerebral ischemia. But controversial results were obtained. Three NCX isoforms, NCX1, NCX2, and NCX3 were distributed selectively in central nervous system, which suggests that each isoform may have different function in cerebral ischemia. In this study we investigated the time-related alteration of gene and protein expressions of NCX1, NCX2, and NCX3 in rat brain cortex after 2 h of transient middle cerebral artery occlusion (tMCAO). Reverse transcription-polymerase chain reaction (RT-PCR) was used to investigate the mRNA levels of each NCX isoform at 2, 6, 12, and 24 h of reperfusion, respectively. Western blot was used to measure the protein expressions of each NCX isoform at 2, 12, and 24 h of reperfusion, respectively. The results showed that NCX1 mRNA level was reduced by 42.1% and 27.8%, respectively, at 2 and 6h of reperfusion and restored to normal level at 12 and 24 h of reperfusion. NCX1 protein was decreased by 36.6% at 2 h of reperfusion and recovered at 12 and 24 h of reperfusion. The mRNA and protein levels of NCX2 and NCX3 did not change significantly over time. These results suggest that NCX1 might play an important role in transient focal cerebral ischemia.
钠钙交换体（NCX）是一种位于许多细胞的质膜中的反向转运蛋白，它可以维持细胞内钙离子稳态。一些研究表明NCX与脑缺血关系密切。但结果存在争议。三种NCX亚型，即NCX1、NCX2和NCX3，在中枢神经系统中选择性分布，这表明每种亚型在脑缺血中可能具有不同功能。在本研究中，我们调查了短暂性大脑中动脉闭塞（tMCAO）2小时后大鼠脑皮质中NCX1、NCX2和NCX3基因和蛋白表达的时间相关变化。分别在再灌注2、6、12和24小时使用逆转录聚合酶链反应（RT-PCR）研究每种NCX亚型的mRNA水平。分别在再灌注2、12和24小时使用蛋白质印迹法测量每种NCX亚型的蛋白表达。结果显示，再灌注2小时和6小时时，NCX1 mRNA水平分别降低了42.1%和27.8%，并在再灌注12小时和24小时恢复到正常水平。再灌注2小时时，NCX1蛋白减少了36.6%，并在再灌注12小时和24小时恢复。NCX2和NCX3的mRNA和蛋白水平随时间没有明显变化。这些结果表明，NCX1可能在短暂性局灶性脑缺血中起重要作用。
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