目的:观察白介素-6(IL-6)对N-甲基-D-天冬氨酸(NMDA)激发的神经元放电活动的影响及其可能的作用机制。方法:用含IL-6、NMDA和JAK抑制剂ACA90的人工脑脊液(ACSF)灌流小脑脑片,利用离体脑片神经元单位放电细胞外记录技术,记录药物对小脑间位核神经元放电的影响。用Western blot法测定间位核神经元NMDA受体亚单位1(NRI)的磷酸化水平。结果:单独用12.5μmol/L和25μmol/LNMDA灌流,神经元放电频率均较基础放电频率增加;用不同浓度IL-6(50,100,200μg/ml)联合NMDA作用后,神经尤的放电频率出现浓度依赖性地降低;AG490可部分阻断IL-6对NMDA兴奋神经元放电的抑制作用。与单独NMDA处理组比较,用IL-6联合NMDA处理神经元后,神经元的NR1磷酸化水平出现浓度依赖性地降低。AG490可阻断IL-6所致的神经元NR1磷酸化水平的降低。结论:IL-6可抑制NMDA激发的小脑间位核神经元的放电兴奋活动;并同时下调神经元的NR1磷酸化水平。
Objective: To study the effect and the possible mechanism of IL-6 on NMDA-excited neuronal discharges of rats in vitro. Methods: The cerebellar slices were prepared and spontaneous discharges of single cerebellar interposed nuclear(IN) neurons were recorded by extracellular recordings. The cerebellar slices were perfused with artificial cerebral spinal fluid(ACSF) containing N-methyl-D-aspartate( NM- DA), IL-6, JAK inhibitor AG490. The changes in firing activities of the neurons treated with the drugs were recorded. The levels of phosphorylation at serine 897 site of NMDA receptor subunit 1 ( NR1 ) in the neurons treated with various drugs mentioned above were detected by Western blot. Results: The discharge rates of the neurons that were treated with IL-6 together with NMDA were significantly lower than those of the neurons treated with NMDA alone. AGd-90 partially blocked the inhibitory effect of IL-6 on the NMDA-stimulated neuronal firing activity. The treatment of the neurons with IL-6 and NMDA led to a concentration-dependent suppression of the phospho-NR1 expression relative to those neurons treated with NMDA alone. AG490 blocked the effect of the IL-6-induced depression of phospho-NR1 expression. Conclusion: IL-6 inhibits NMDA-stimulated neuronal firing activity, and simultaneously down-regulates the phosphorylation of NR1 at serine 897 site.