NMDA诱导新生大鼠脑组织NMDA受体-1的表达

Expression of NMDA receptor-1 induced by NMDA in the brain of neonatal SD rats

目的:了解N-甲基-D-天冬氨酸(N-M ethyl-D-Aspartate,NMDA)诱导的脑组织内NMDA受体-1(NR1)表达的规律。方法:90只7日龄新生SD大鼠随机分为正常对照组(n=6)、NMDA注射组(包括10 nmol NMDA微量注射后0 m in,15 m in,30 m in,1 h,2 h,4 h时间点组,和10 nmol,20 nmol和50 nmolNMDA组,各组n=6)。采用经心脏灌注固定、切片制备脑组织标本及荧光免疫组化染色和三氯四氮唑(2,3,5-triphenyltetrazolium chloride,TTC)染色方法。结果:10 nmol NMDA注射后30 m in,沿注射轨迹边缘开始出现少量NR1阳性染色细胞,注射后1 h时NR1阳性细胞亦出现在海马回CA1区和邻近脑室边缘的下丘脑区,且数目迅速增多,并主要集中在注射侧大脑半球,注射后2 h及4 h该阳性细胞数目与1h无明显差异。NMDA微量注射后2 h,50 nmol NMDA所致的NR1表达较10nmol和20 nmol明显增强,且细胞壁出现皱缩、细胞核稍固缩。各浓度NMDA微量注射后2 h,TTC染色均大致正常。结论:NMDA诱导的NR1表达在经过短时间的延迟后呈一定的时效和量效关系,临床上可考虑应用该延迟时段作为“治疗窗”,采用NMDA受体拮抗剂治疗与NMDA受体激活密切相关的中枢神经系统疾病。

Objective To determine the regulation of the expression of NMDA receptor-1 induced by NMDA in the brain of neonatal SD rats. Methods Neonatal SD rats （n = 90） were randomly divided into normal control （n = 6） and NMDA injected group （subdivided into 10 nmol-0 min, 15 min,30 min, 1 h,2 h,4 h groups, and 10, 20, 50 nmol groups, each n = 6）. NMDA fluorescent inmmunohistological staining and TTC （2,3,5-triphenyltetrazolium chloride） staining techniques were used. Results At 30 min after the injection of 10 nmol NMDA, a few NR1 positive cells could be observed along the injection tract. At 1 h after the injection, NR1 positive cells in large quantity could be observed in the hippocampal CA1 region and paraventricular thalamus of the ipsilateral hemisphere. The number and location of positive cells at 2 h and 4 h after the injection were not much different from that at 1 h after the injection. At 2 h after injection, stronger NR1 expression was observed in the 50 nmol injection group. In addition, slight crinkle of the cell wall with mild condensation of the nuclei was also observed in the 50 nmol injection group. At 2 h after the injection, no abnormality was observed in 10, 20, or 50 nmol group after TFC staining. Conclusion The NR1 induced by NMDA is expressed in a time-dependent and dose-dependent pattern after a short period of ＂delay＂, providing a possible ＂therapeutic window＂ for using NMDA＂ receptor antagonist to treat diseases relating to the NMDA receptor activation.