帕金森病运动并发症与谷氨酸受体亚型GluR1Ser845磷酸化关系的实验研究

Relationship between motor complications of Parkinson's disease and phosphorylated GluR1Ser845

目的探讨帕金森病(PD)长期左旋多巴治疗的运动并发症与纹状体神经元谷氨酸受体1的845位丝氨酸(GluR1Ser845)磷酸化的关系。方法通过6-羟基多巴立体定向注射至大鼠前脑内侧前脑束建立PD动物模型,然后左旋多巴甲酯腹腔注射治疗(25mg.kg-1.d-1,每天2次)22d,评估旋转时间、关期发生频率情况;采用免疫荧光与蛋白印迹法检测纹状体区谷氨酸受体1(GluR1)亚细胞分布及GluR1Ser845磷酸化的表达情况。结果PD大鼠长期应用左旋多巴处理后呈现旋转时间逐渐缩短、关期频率递增的趋势,与人类症状波动和开关现象具有相似特征。PD大鼠损伤侧纹状体细胞膜上GluR1和GluR1Ser845磷酸化的数量分别减少至73.0%±4.8%和42.0%±5.6%;长期左旋多巴处理后使损伤侧纹状体细胞膜上GluR1和GluR1Ser845磷酸化的数量分别增加至104.0%±5.5%和112.0%±3.4%;然而损伤侧纹状体GluR1总蛋白数量未发生明显变化。这些改变特异性发生在小清蛋白阳性的中间神经元上。结论长期左旋多巴治疗的运动并发症可能与小清蛋白阳性的神经元上GluR1的亚细胞分布及GluR1Ser845磷酸化的改变有关。

Objective To explore the relationship between motor complications of Parkinson＇ s disease （PD） with chronic L-dopa treatment and striatal phosphorylated GluR1Ser845. Methods The hemi-parkinsonian rat model was produced by injecting stereotaxically 6-OHDA to right medial forebrain bundle（MFB）. Then the hemi-parkinsonian rat was treated intraperitoneally with L-dopa methylester （25 mg · kg^-1· d^-1, twice one day） for 22 days and rotational duration and frequency of off period were respectively estimated. After they were sacrificed, their subcellualr distribution of GluR1 and GluR1 Ser845 phosphorylation was observed with immunofluorescence and Western blot. Results After the chronic treatment with L-dopa methylester, PD rats displayed shortened rotational duration and increased frequency of off period, which was similar to fluctuations of the symptoms and on-off phenomenon in PD patients. In the lesioned striatum of PD rats, the amount of GluR1 and phosphorylated GluR1 Ser845 in striatal membrane was reduced to 73.0% ±4. 8% and 42.0% ±5.6%, respectively, compared with those non-lesioned. After chronic treatment of PD rats with L-dopa, the amount of GluR1 and phosphorylated GluR1Ser845 in striatal membranes were increased to 104.0% ±5.5% and 112. 0% ±3.4%. These unique changes occurred only in parvalbumin-positive interneurons. Conclusions These findings suggest that subcellular distribution and phosphorylation state of GluR1Ser845 in parvalbumin-positive interneurons may play a significant role in the pathogenesis of motor complications of chronic L-dopa treatment for PD.