【作者】 江波；

【导师】 陈建国；

【作者基本信息】 华中科技大学 ， 药理学， 2012， 博士

【摘要】 第一部分磷酸肌醇耦联多巴胺受体激动剂SKF83959的抗抑郁作用目的：抑郁症是当前社会日益严重的一种精神疾病,但目前临床上常用的抗抑郁药使用周期长,毒副作用较多,不能满足临床需要。诸多研究表明多巴胺能神经系统参与抑郁症的发生发展,如多巴胺D2受体激动剂喹吡啰等具有强效抗抑郁作用。磷酸肌醇耦联多巴胺D1样受体(phosphatidylinositol-linked D1dopamine receptor; PI-D1受体)是近年来新发现的除D1、D2这两类经典多巴胺受体外的又一新型多巴胺受体,但对于该受体的激动剂是否具有抗抑郁效应尚不清楚。因此,本部分实验拟采用新型PI-D1受体激动剂SKF83959研究其在抑郁症中的作用。方法：采用腹腔注射给药、脑区定位给药、强迫游泳实验(FST)、自发活动测试、慢性社会挫败应激(CSDS)、糖水消耗测试、社会接触实验、脑片免疫荧光、高尔基染色等方法。结果：行为学实验发现,慢性给予PI-D1受体激动剂SKF83959在FST与CSDS实验中表现出明显的抗抑郁作用,且不影响动物的自发活动,该作用是通过多巴胺D1样受体,而非D2样受体介导。另外,我们发现SKF83959可拮抗慢性应激所致的海马神经元发生受损和树突棘减少。结论：慢性给予PI-D1受体激动剂SKF83959具有抗抑郁作用。第二部分磷酸肌醇耦联多巴胺受体激动剂SKF83959抗抑郁作用的机制目的：抑郁症的发病机制复杂,涉及到多种信号通路及蛋白靶点,其中脑源性神经营养因子(BDNF)信号通路系统、5-羟色胺(5-HT)能系统与下丘脑-垂体-肾上腺轴(HPA)与其高度相关。而PI-D1受体激动剂SKF83959抗抑郁作用的分子机制尚不清楚,因此,本实验拟探讨SKF83959抗抑郁的作用机制。方法：采用腹腔注射给药、脑区定位给药、强迫游泳实验(FST)、自发活动测试、慢性社会挫败应激(CSDS)、糖水消耗测试、社会接触实验、western blotting、 RT-PCR、放射免疫检测、脑片免疫荧光、高尔基染色等技术方法。结果：SKF83959可逆转慢性应激所致的海马BDNF-cAMP反应元件结合蛋白(CREB)信号通路功能下调,但不影响前额叶皮质(mPFC)与伏隔核(NAc)脑区,也不影响神经生长因子(NGF)、神经营养因子3(NT3)与神经营养因子4(NT4)的水平。进一步实验发现PLC/IP3信号通路抑制剂和BDNF受体酪氨酸激酶B(TrkB)抑制剂K252a均可拮抗SKF83959的抗抑郁效应,提示其作用机制与神经元PLCβ/IP3/Ca2+信号通路和BDNF-TrkB信号通路有关。而色氨酸羟化酶抑制剂PCPA不能拮抗SKF83959的抗抑郁作用,提示该作用不是由单胺能神经系统介导。另外,SKF83959不能逆转慢性应激所致的血清皮质酮含量增加,提示该作用与HPA轴无关。结论：PI-D1受体激动剂SKF83959的抗抑郁作用是通过PLCβ/IP3通路介导,促进海马BDNF信号通路和神经元生长所致。更多还原

【Abstract】 Part I Effects of phosphatidylinositol (PI)-linked D1-like receptor agonist on major depressive disorderAim:Depression is a group of syndromes characterized by notable and persistent mood disorders. Although current therapy improves depression, the symptoms fail to resolve completely in as many as half of cases. Remission rates are even worse for those who have failed initial medication trials. Thus, the antidepressants with higher efficacy and fewer side effects are needed. Growing evidence indicates a relationship between dopamine system and depression, and some dopamine receptor agonists have been proved to produce antidepressant effects.The dopamine receptor that activates the PLC/IP3pathway has been called the phosphatidylinositol (PI)-linked D1-like receptor (PI-D1receptor), a novel dopamine D1-like receptor. However, it remains unknown that whether activation of this receptor could modulate depression. We thus did a series of experiments to explore this hypothesis.Methods:Intraperitoneal injection, intracerebroventricular injection, forced swim test (FST), open field test, chronic social defeat stress (CSDS), sucrose preference test, social interaction test, double-labeling immunofluorescence and golgi silver staining were used in this section.Results:Behavioral experiments showed that activation of PI-D1receptor by SKF83959could produce robust antidepressant-like effect without affecting spontaneous locomotor activity, and this effect was associated with D1-like receptor activation but independent of D2-like receptor. Molecular biology techniques revealed that SKF83959treatment also counteract the deficiency of neurogenesis and dendrite spine density caused by CSDS. Conclusion:Chronic activation of PI-D1receptor by SKF83959treatment produces effective antidepressant efficacy in various animal models of depression. Part II The antidepressive mechanism of phosphatidylinositol (PI)-linked D1-like receptor agonist SKF83959Aim:The pathophysiology of depression is complex and involves many moleculars and proteins, like BDNF cascade, serotonergic system and HPA system. Having demonstrated the antidepressant effects of SKF83959, we then investigated the antidepressive mechanism of SKF83959by using various methods.Methods:Intraperitoneal injection, intracerebroventricular injection, forced swim test (FST), open field test, chronic social defeat stress (CSDS), sucrose preference test, social interaction test, western blotting, RT-PCR, radioimmunoassay test, double-labeling immunofluorescence and golgi silver staining were used in this section.Results:Molecular biology techniques revealed that SKF83959treatment restore the stress-induced decrease in hippocampal BDNF-CREB signaling pathway, and produce no effects on hippocampal NGF, NT3, and NT4. We also proved that the PI-D1receptor-mediated effect is selective to hippocampus. By using various inhibitors, we further demonstrated that SKF83959treatment produced antidepressant-like effects through PLC/IP3signaling pathway and BDNF-TrkB signaling cascade, and serotonin depletion does not alter the effects of SKF83959. Furthermore, stress-evoked corticosterone responses are normal in the SKF83959-treated mice, suggesting that activation of PI-D1receptor has no influence on the dysfunction of hypothalamus-pituitary-adrenal (HPA) axis.Conclusion:Chronic SKF83959treatment produces effective antidepressant efficacy through PLC/IP3pathway, and by modulating the function of hippocampal BDNF system and neurogenesis.更多还原