Abstract: To explore long-term changes of NMDAR subunit mRNA expression induced by early magnesium-free treatment in developing cortical neurons of rat. The seizure model was recurrent epileptiform discharges induced by transient magnesium-free media treatment in the primary cultured embryo cortical neurons of rat. According to different treatment to cortical neurons at cultured day 6, three groups were divided: regular DMEM medium (CONT1)、regular extracellular solution medium (CONT2) and magnesium-free extracellular solution medium (MGF). The neuronswere exposed to above three media for 3h in cultured day 6, and then cultured in regular DMEM medium again. The expression of NMDAR subunit NR1, NR2A, and NR2B mRNA was measured using fluorescent real-time quantitative RT-PCR at different cultured day (7、12、17). Our results in group MGF showed that NR1 mRNA expression decreased at d7 and increased at d12 (p<0.05), NR2A mRNA expression decreased at d12 and increased at d17 (p<0.05), and NR2B mRNA expression increased at d7 and d17 (p<0.05). There were not statistic significant differences of mRNA expression of NR1 at d17, NR2A at d7, and NR2B at d12 among three groups (p>0.05). There were significant alterations of proportion of NR1/NR2A, NR1/NR2B and NR1/NR2A/NR2B mRNA expression at d7, d12 and d17 in group MGF. The change of NMDAR subunit mRNA expression may be resulted by long-term changes of early magnesium-free treatment in developing cortical neurons of rat.

Key words: seizure, long-term, N-methyl-D-aspartate, receptors, mRNA

摘要： 以原代培养的大鼠大脑皮层神经元无镁诱导的反复惊厥样放电为模型，根据对培养6d(天)皮层神经元的不同处理分为3组：正常DMEM培养液组（CONT1）、正常细胞外液组（CONT2）和无镁细胞外液组（MGF）。神经元在上述3种液体中孵育3h，然后恢复正常DMEM培养液继续培养，在培养7、12及17d时应用实时定量PCR测定了发育中大鼠皮层神经元无镁细胞外液处理后NMDA受体亚基NR1、NR2A与NR2B mRNA表达的变化。结果显示: MGF组NR1 mRNA表达在培养7d时明显降低，培养12d时明显升高（p<0.05）；NR2A mRNA表达在培养12d时明显降低，培养17d时明显升高（p<0.05）；NR2B mRNA表达在培养7d与17d时明显升高（p<0.05）。而培养17d NR1 mRNA表达、7d NR2A mRNA表达及12d的皮层神经元NR2B mRNA表达3组中两两比较无统计学差异（p>0.05）。MGF组NR1/NR2A、NR1/NR2B和NR1/NR2A/NR2B在培养7、12与17d皮层神经元均有明显的变化。可见早期无镁细胞外液处理可以诱导发育中大鼠皮层神经元远期NMDAR亚基mRNA表达的改变。

关键词: 惊厥, 远期, N-甲基-D-天冬氨酸, 受体, mRNA