NMDA微量注射对脑皮质细胞磷酸化NMDA受体-1亚基表达的影响

Expression of phosphorylated NMDA receptor 1 in the cerebral cortex after NMDA microinjection in vivo

摘要:

目的：N-甲基-D-天冬氨酸（NMDA）受体激活在多种脑神经细胞损伤的病理生理过程中起重要的作用。该研究的目的是了解NMDA直接诱导的细胞毒性反应对脑皮质神经细胞S897位点磷酸化的NMDA受体-1亚基（phospho-NR1 S897）表达的影响。方法：7日龄SD大鼠40只，随机分为正常对照组和NMDA微量注射组（10 mmol NMDA脑皮质内注射，于注射后1 h断头取材），应用TTC（2,3,5-triphenyltetrazolium chloride）染色和荧光免疫组化染色并比较各组荧光强度OD值。结果：各组脑组织切片TTC染色均大致正常；免疫荧光染色显示正常对照组脑皮质phospho-NR1 S897高表达，NMDA注射侧脑皮质phospho-NR1 S897 表达明显下调，各组荧光强度OD值分别为：正常对照组1.364±0.268，NMDA注射对侧1.285±0.336，NMDA注射侧0.366±0.087，与前2组比较差异有显著性（P<0.01）。结论：NMDA直接诱导的细胞毒性反应使脑皮质细胞S897位点的磷酸化NR1亚基的表达显著降低，与HI导致的损伤相类似，进一步证实了缺氧缺血性脑损伤中“HI-NMDA-phospho-NR1 S897去磷酸化-细胞损伤”损伤途径的重要性。［中国当代儿科杂志，2007，9（1）：51-53］

Abstract:

OBJECTIVE: The activation of N-methyl-D-aspartate(NMDA) receptors plays critical roles in the pathogenesis of diseases of the brain. This study aimed to examine the expression of phosphor-NR1 S897 in the cerebral cortex after NMDA microinjection in vivo. METHODS: Forty seven-day-old Sprague-Dawley rats were randomly assigned into normal control and NMDA injection groups. The rats from the NMDA injection group were injected with 10 mmol of NMDA and were sacrificed 1 hr after injection. 2, 3, 5-triphenyltetrazolium chloride (TTC) and fluorescent immunohistochemical stainings were conducted and the fluorescence intensity OD value between the two groups was compared. RESULTS: TTC staining from the two groups was normal. Expression of phosphor-NR1 S897 in the cerebral cortex of the ipsilateral hemisphere to injection in the NMDA injection group decreased significantly compared with the normal control group, with OD values of 0.366±0.087 vs 1.364±0.268 (P<0.01). CONCLUSIONS: NMDA microinjection, as a hypoxia-ischemia (HI) insult, significantly decreased the expression of phosphor-NR1 S897. This indicates the importance of the HI-NMDA-phospho-NR1 S897 dephosphorylation-cell damage pathway in HI brain damage.［Chin J Contemp Pediatr, 2007, 9(1):51-53］