中文摘要：

目的：研究慢性不可预知性应激诱导的抑郁大鼠纹状体内多巴胺受体D1型（dopaminereceptorD1，DRD1）和microRNA-504（miR-504）的表达，探讨miR-504是否介导了DRD1基因表达参与调控慢性不可预知性应激诱发大鼠抑郁的发生。方法：将10周龄雄性SD大鼠随机分为实验组和对照组。实验组大鼠接受连续21天慢性不可预知性应激，对照组不接受任何实验性处理。两组大鼠均于13周龄时，采用强迫游泳测验、糖水偏爱测验和旷场试验评定大鼠的抑郁水平，以实时定量荧光RT-PCR（qRT-PCR）检测纹状体内DRDlmRNA和miR-504的表达水平，以免疫印迹法（WesternBlot）检测纹状体DRD1蛋白质表达水平。结果：与对照组大鼠相比，实验组大鼠直立次数和爬行总路程均减少，而被动漂浮时间延长；两组大鼠的大便颗数和糖水偏爱率差异均不显著。实验组大鼠纹状体内DRDI蛋白和miR-504表达量均降低，而DRD1mRNA的表达量与对照组比较差异不显著。皮尔逊相关分析显示，两组大鼠纹状体内DRD1蛋白水平与大鼠的被动漂浮时间呈负相关，而与其他的行为测验水平无明显相关；两组大鼠纹状体内miR-504水平与行为测验水平均无明显相关。结论：慢性不可预知性应激诱导大鼠产生了抑郁样行为并能降低纹状体DRD1蛋白和miR-504的表达；miR-504可能并不参与纹状体内DRD1基因表达参与调控慢性不可预知性应激诱发大鼠抑郁的发生过程。

英文摘要：

Objective： To study the expression of dopamine receptor DI（DRD1） and microRNA-504（miR-504） in striaturn of depressed rat induced by the chronic unpredictable stress, and to investigate whether miR-504 is involved in the regulation of the process in which DRD1 gene mediated rats＇ depressive behaviors during chronic unpredictable stress response. Methods： Male SD rats at the age of 10 weeks were randomly divided into two groups. The stress group rats received chronic unpredictable stressors for continuous 21 days while the control group rats received no experimental handle. When they grew up to 13 weeks, depressive behaviors were assessed with forced swimming test, sucrose preference test and open field test. The expressions of DRD 1 mRNA, miR-504 and DRD 1 protein in rats＇ striatum were detected by real-time Polymerase Chain Reaction（Real-time PCR） and Western Blotting respectively. Results： In the open field test, the number of vertical activity and total distance in stress group rats were significantly less than that in control group, the number of the fecal pellets was not different between two groups. In the forced swimming test, the floating time in the stress group rats is significantly longer than that in control group. In the sucrose preference test, there was no difference of the sucrose prefer- ence rate between two groups： The expression of DRD1 protein and miR-504 in stress group were significantly lower than in control group. The expression of DRD1 mRNA in stress group was not different compared with control group. Pearson correlation analysis revealed that the expression of DRD 1 protein in rat striatum was negatively correlated with the floating time. Gonclusion： Chronic unpredictable stress induces the depressive behaviors of the rats, leading to the corresponding changes of expression of DRD1 protein and miR-504 in rat striatum. MiR-504 might not be involved in the regulation of DRD 1 gene expression in process which chronic unpredictable stress induces the depressive beh