【作者】 李丹；

【导师】 曹非；

【作者基本信息】 华中科技大学 ， 神经病学， 2016， 硕士

【摘要】 【目的】左旋多巴诱发的异动症(L dopa induced dyskinesia,LID)是长期接受左旋多巴治疗的帕金森病(Parkinson’s disease,PD)患者较为严重的并发症,而当今的治疗方法很有限。有实验研究表明非选择性乙酰胆碱受体(n ACh R)激动剂尼古丁可减轻左旋多巴诱发的异动症表现,但其确切机制仍不清楚。该实验通过检测尼古丁对异动症大鼠纹状体多巴胺D1受体(D1 dopamine receptor,D1R)介导的传导通路的影响,阐述尼古丁减轻左旋多巴诱发的异动症的作用机制。【方法】使用6羟基多巴胺(6 OHDA)毁损制备偏侧帕金森病大鼠模型,脑立体定向注射位点为右侧前脑内侧束。然后为建立稳定的异动症大鼠模型,给予制作成功的PD大鼠左旋多巴(10mg/kg)和苄丝肼(2.5mg/kg)腹腔注射,连续2周。然后给予尼古丁(0.1mg/kg,n=7)或生理盐水(1ml/kg,n=7),连续22天,期间继续给予左旋多巴治疗,且生理盐水、尼古丁在给予左旋多巴治疗10min前注射。在注射L dopa后14d及生理盐水或尼古丁治疗后1d、21d进行AIM评分,通过免疫组织化学法检测TH,western blot法检测ERK、p ERK和ΔFos B的表达水平,real time PCR法检测前强啡肽原和前脑啡肽原m RNA的表达水平,并通过透射电镜观察纹状体区神经突触变化。【结果】左旋多巴可诱发帕金森病大鼠产生异常不自主运动。急性尼古丁治疗对LID没有治疗作用(P>0.05),而长期尼古丁治疗可减轻大鼠的异动症表现(P<0.05),且不影响左旋多巴引起的对侧旋转行为(P>0.05)。Western blot法提示LID大鼠纹状体区p ERK1/2、ΔFos B的表达水平明显增多(P<0.05),经尼古丁治疗后,其表达量均明显下降(P<0.05)。RT PCR法提示LID大鼠纹状体区强啡肽原、脑啡肽原的m RNA表达水平均均较正常大鼠明显升高(P<0.05),经尼古丁治疗后,强啡肽原m RNA表达水平下降(P<0.05),而对脑啡肽原m RNA表达水平无明显影响(P>0.05)。透射电镜观察纹状体区突触,显示LID大鼠纹状体区突触后致密物质(postsynapse density,PSD)宽度增大,突触间隙变窄,经尼古丁治疗后减轻了上述突触结构的变化。【结论】尼古丁可通过调节多巴胺D1受体介导的传导通路中相关因子的表达,改善纹状体神经突触的结构,发挥减轻左旋多巴诱发的异动症作用。更多还原

【Abstract】 Objective: Abnormal involuntary movements(AIMs) or dyskinesias are a serious complication of long-term L-dopa treatment of Parkinson’s disease(PD), for which there are few treatment options. Accumulating preclinical data show that the nonselective nicotinic acetylcholine receptors(n ACh R) agonist nicotine decreases L-dopa-induced dyskinesia(LID), but the concrete mechanism is not fully understood. Here we determined the possible mechanisms of nicotine in reducing LID in the rat model.Methods: To address this issue, we produced a rat model of PD using 6-hydroxydompamine(6-OHDA) injections, and valid PD rats(n=14) were first administered i.p. L-dopa/benserazide(10/2.5 mg/kg) once daily two weeks. Then, nicotine(0.1 mg/kg, n=7) or vehicle(1ml/kg, n=7) was administered i.p. prior to L-dopa/benserazide treatment for three weeks. The acute and chronic effects of nicotine treatment on abnormal involuntary movements(AIMs) and L-dopa-induced rotations were investigated in LID rats. We measured the expression of ΔFos B、ERK and p-ERK through Western blot, detected the m RNA levels of preprodynorphin and preproenkephalin by real-time PCR and observed the changes of synaptic ultrastructure by Electron microscopy technique.Results: L-dopa elicited increased dyskinesia in PD rats. Acute nicotine treatment had no effect on LID, but chronic nicotine administration reduced LID in rats with dyskinesia. Importantly, L-dopa-induced rotations were not affected by chronic treatment with nicotine. Chronic nicotine administration did not modify L-dopa-induced increase in striatal preproenkephalin(PPE) m RNA, but attenuated the phosphorylated levels of extracellular signal-regulated kinases 1/2(ERK1/2) and the expression of ΔFos B and preprodynorphin(PDyn) m RNA of PD rats with dyskinesia. Electron microscopy technique results showed that the postsynapse density(PSD) depth was much thicker and synapse cleft width was narrower in the L-dopa-treated rats, while nicotine administration attenuated the changes of synaptic ultrastructure by L-dopa in striatum.Conclusion: Together, our results demonstrate that nicotine modulates the development of dyskinesia by targeting D1 dopamine receptor(D1R) mediated intracellular signaling, and suggest that nicotine may help to ameliorate LID.更多还原