不同剂量左旋多巴对偏侧帕金森病大鼠行为学及多巴胺D2受体表达数的影响

目的：研究不同剂量左旋多巴对偏侧帕金森病大鼠行为学及多巴胺D₂受体表达数的影响，并对其相应机制进行探讨。方法：采用6-羟多巴胺（6-OHDA）制备偏侧PD大鼠模型，用免疫组化染色法检测PD模型大鼠分别给予左旋多巴不同剂量（10 mg·kg^-1·d^-1,50 mg·kg^-1·d^-1，100 mg·kg^-1·d^-1）腹腔注射15 d前后纹状体部位的多巴胺D₂受体表达数、观察大鼠行为学改变。结果：成功PD模型大鼠30 min旋转圈数与损毁侧及其健侧的D₂受体表达数增加百分数呈线性相关（r=0.927，P<0.01），大剂量左旋多巴干预后PD大鼠的旋转圈数明显少于对照组（P<0.05），且损毁侧纹状体多巴胺D₂受体表达数明显少于对照组（P<0.01）。结论：大剂量左旋多巴干预能明显改善PD大鼠的旋转行为，并使纹状体多巴胺D₂受体明显下调。

Effects of different doses of L-dopa on rotational behavior and amounts of cells expressing D2 receptors in hemiparkinsonian rats

AIM：To observe the effects of different doses of L-dopa on the rotational behavior and amounts of cells expressing D₂ receptors in striatum in hemiparkinsonian rats.METHODS：A hemiparkinsonian model was established in rats by pretreatment with 6-hydroxydopamine.The D₂ receptor expression were detected by immunohistochemical staining.The numbers of rotations induced by apomorphine was counted within 30 min before and after L-dopa (10 mg·kg^-1·d^-1,50 mg·kg^-1·d-^-1 or 100 mg·kg^-1·d^-1,ip) was introduced to Parkinson’s disease (PD) model rats for 15 days.RESULTS：In successful PD model rats,the increased percentage of D₂ receptor in lesioned side compared with intact side was associated linearly with the numbers of rotations within 30 min (r=0.927,P<0.01).After high dose of L-dopa intervention to PD model,the numbers of rotations decreased significantly (P<0.05),the amounts of cells expressing D₂ receptor at the lesioned side striatum decreased significantly (P<0.01).CONCLUSION：After high dose of L-dopa intervention,rotation behavior of PD rats improves,and D₂ receptor is down-regulated significantly.