ABT-724对SHR大鼠行为及小脑多巴胺D4受体表达影响的研究

发布时间：2018-07-12 09:24

本文选题：注意缺陷多动障碍 + 多巴胺D4受体　；参考：《山东大学》2012年硕士论文

【摘要】：[背景] 注意缺陷多动障碍(attention deficit hyperactivity disorder, ADHD)是一种常见的儿童期起病的神经行为障碍,主要表现为与发育水平不相称的一系列行为异常,如不分场合的多动、冲动以及注意力分散。ADHD是一种影响终身的慢性疾病,若不早期进行干预治疗,随着年龄的增长,70%的患儿症状持续至青春期,30%的患儿症状持续至成人,对患者的学业、行为调控、社会生活等方面产生广泛而消极的影响。其发病机制至今尚未阐明。研究表明,ADHD的发生与发展可能与多巴胺D4受体异常表达有关。既往对ADHD发病机制的研究主要集中在前额叶皮层,纹状体和基底节等脑区。近年来研究者对ADHD患儿的脑部磁共振成像扫描时发现其小脑总容量尤其是小脑蚓部容量比正常儿童显著减少。并且人们对小脑在注意力、冲动情绪控制、认知等方面的作用有了新的认识。这些发现为深入研究ADHD的发病机制提供了新的切入点。本研究选择最常用的ADHD动物模型即自发性高血压大鼠(spontaneously hypertensive rat, SHR)作为研究载体,采用选择性多巴胺D4受体激动剂ABT-724进行干预,观察ABT-724对SHR大鼠认知行为及其小脑多巴胺D4受体表达的影响,探讨小脑多巴胺系统功能异常在ADHD发病机制中的可能作用,并为寻找治疗ADHD的新靶点提供理论依据。 [方法]： 1.观察幼年SHR/WKY/SD大鼠的行为学表现。利用开场试验、Morris水迷宫、Lat迷宫三种试验方法,分别观察SHR/WKY/SD大鼠自发活动水平、空间学习和记忆能力、非选择性注意力。 2.研究选择性多巴胺D4受体激动剂ABT-724对SHR行为的影响。分别用ABT-724低(0.04mg/kg)、中(0.16mg/kg)、高(0.64mg/kg)三个剂量及哌甲酯(5mg/kg)干预SHR,并用未干预(生理盐水1ml/kg) SHR作为对照,利用开场试验、Morris水迷宫、Lat迷宫,观察干预前后SHR自发活动水平、空间学习和记忆能力、非选择性注意力。 3.探讨选择性多巴胺D4受体激动剂ABT-724对SHR小脑多巴胺D4受体表达的影响。行为学测试结束后,利用免疫组织化学及实时定量RT-PCR技术检测SHR/WKY/SD大鼠及干预前后SHR小脑多巴胺D4受体的表达。 [结果]： 1.观察幼年SHR/WKY/SD大鼠的行为学表现。在开场实验中,SHR穿越格子数(94.50±22.51)较WKY(6±3.12)和SD大鼠(63.63±22.33)明显增多(p均0.05)。在Morris水迷宫中,SHR大鼠(21.38±5.01)与SD大鼠(41.13±6.10)相比,空间记忆能力降低(p0.05)；WKY大鼠(24.88±9.31)则表现出明显的漂浮特征。SHR大鼠在Lat迷宫中直立次数(138.63±31.89)明显多于WKY(19.36±17.69)及SD大鼠(76.88±32.80)(p0.05),后二者无明显差别(p0.05)。 2.研究选择性多巴胺D4受体激动剂ABT-724对SHR行为的影响。哌甲酯及ABT-724干预后的SHR大鼠穿越格子数(分别为70.67±8.59,76.50±10.75,79.17±10.44,65.67±20.62)较盐水组大鼠(130.33±11.40)明显减少(p均0.05)。在Morris水迷宫中,干预后的SHR大鼠空间记忆能力(分别为52.50±4.04,52.17±2.99,61±8.15,53.83±9.87)与盐水组大鼠(38.83±7.17)相比明显提高(p均0.05)。在Lat迷宫中,干预后的SHR大鼠直立次数(分别为57.17±5.67,60.83±8.28,55.17±9.45,65.33±9.50)与盐水组大鼠(78.00±13.84)相比明显减少(p均0.05)。 3.探讨选择性多巴胺D4受体激动剂ABT-724对SHR小脑多巴胺D4受体表达的影响。SHR小脑多巴胺D4受体累计光密度值(IOD)(2016900±494060)及mRNA表达(0.63±0.12)均较WKY/SD大鼠显著减低(p均0.05),后二者比较无明显差别。ABT-724低、中、高剂量和哌甲酯干预后SHR小脑多巴胺D4受体IOD及nRNA表达较盐水组均显著升高(p均0.05)。 [结论]： 1. SHR幼鼠作为ADHD最常用的一种动物模型,与WKY、SD大鼠相比较,分别在开场试验、Lat迷宫、Morris水迷宫中表现出明显的多动、冲动,注意力不集中以及认知功能障碍。本课题在增加了另一品系大鼠(即SD大鼠)的基础上,对SHR的自发活动水平、非选择性注意力、认知功能再次进行检测、评估,为进一步的研究奠定了理论基础。 2. ABT-724干预后的SHR表现出白发活动减低、认知功能及非选择性注意力改善,其效果与哌甲酯干预后效果相近,提示选择性多巴胺D4受体激动剂ABT-724对SHR的行为认知有明显的改善作用。 3.在SHR/WKY/SD大鼠小脑多巴胺D4受体表达的比较中,SHR该脑区多巴胺D4受体表达较其两个对照组明显下降,此结果为进一步的干预试验提供了理论基础。ABT-724可引起SHR大鼠小脑多巴胺D4受体表达增多,此作用与哌甲酯干预后效果相同,表明多巴胺D4受体激动剂的适当刺激在改善SHR行为认知活动的同时可引起小脑多巴胺D4受体表达升高。提示了小脑多巴胺D4受体的异常表达可能与ADHD认知功能障碍有关,也为寻找ADHD的新治疗靶点提供了理论依据。
[Abstract]:[background]
Attention deficit hyperactivity disorder (attention deficit hyperactivity disorder, ADHD) is a common onset of childhood neurobehavioral disorders, mainly manifested in a series of behavioral abnormalities disproportionate to the level of development, such as undivided hyperactivity, impulsiveness, and distracted.ADHD, a chronic disease that affects life for life, if not early Intervention treatment, with the age of age, 70% of the children's symptoms continue to puberty, 30% of the children's symptoms continue to adult, the patient's academic, behavioral regulation, social life and other aspects of a wide and negative impact. Its pathogenesis has not yet been clarified. The study shows that the occurrence and development of ADHD may be abnormal with dopamine D4 receptor. Previous studies of the pathogenesis of ADHD were mainly focused on the frontal cortex, striatum, and basal ganglia. In recent years, the researchers found that the total volume of cerebellum, especially the cerebellar vermis, was significantly reduced in the brain magnetic resonance imaging (MRI) scan of children with ADHD. There is a new understanding of the role of control and cognition. These findings provide a new entry point for the in-depth study of the pathogenesis of ADHD. This study selects the most commonly used ADHD animal model, spontaneously hypertensive rat (SHR), as the research carrier and selective dopamine D4 receptor agonist ABT-724. The effects of ABT-724 on the cognitive behavior of SHR rats and the expression of dopamine D4 receptor in the cerebellum were observed. The possible role of the dysfunction of the cerebellar dopamine system in the pathogenesis of ADHD was explored, and the theoretical basis for finding new targets for the treatment of ADHD was provided.
[method]:
1. the behavioral performance of young SHR/WKY/SD rats was observed. Using the open field test, the Morris water maze and the Lat maze, the spontaneous activity level, the spatial learning and memory ability, and the non selective attention of the SHR/WKY/SD rats were observed respectively.
2. study the effect of selective dopamine D4 receptor agonist ABT-724 on the behavior of SHR. Using ABT-724 low (0.04mg/kg), medium (0.16mg/kg), high (0.64mg/kg) three doses and methylphenidate (5mg/kg) intervention SHR, and using non intervention (physiological saline 1ml/kg) SHR as control, using open trial, Morris water maze, labyrinth, observed before and after intervention spontaneously. Activity level, spatial learning and memory ability, and non selective attention.
3. to investigate the effect of selective dopamine D4 receptor agonist ABT-724 on the expression of SHR cerebellar dopamine D4 receptor. After the end of the behavioral test, immunohistochemistry and real-time quantitative RT-PCR technique were used to detect the expression of SHR cerebellar dopamine D4 receptor in SHR/WKY/SD rats.
[results]:
1. the behavior of young SHR/WKY/SD rats was observed. In the opening experiment, the number of SHR crossing lattices (94.50 + 22.51) was more than WKY (6 + 3.12) and SD rats (63.63 + 22.33) significantly increased (P 0.05). In the Morris water maze, the spatial memory ability of SHR rats (21.38 + 5.01) and SD rats (41.13 + 6.10) decreased (P0.05); WKY rats (24.88 + 9.31) The erect frequency of.SHR rats in the Lat maze (138.63 + 31.89) was significantly more than that of WKY (19.36 + 17.69) and SD rats (76.88 + 32.80) (P0.05), and there was no significant difference in the latter two (P0.05).
2. study the effect of selective dopamine D4 receptor agonist ABT-724 on SHR behavior. The number of traversing lattices in SHR rats after methylphenidate and ABT-724 (70.67 + 8.59,76.50 + 10.75,79.17 + 10.44,65.67 + 20.62 respectively) decreased significantly (130.33 + 11.40) in saline group (P 0.05). In Morris water maze, the spatial memory of SHR rats after the dry prognosis The ability (52.50 + 4.04,52.17 + 2.99,61 + 8.15,53.83 + 9.87 respectively) was significantly increased (P 0.05) compared with the saline group (38.83 + 7.17). In the Lat maze, the erect number of SHR rats (57.17 + 5.67,60.83 + 8.28,55.17 + 9.50, respectively) in the Lat maze was significantly lower than that in the saline group (78 + 13.84) (P 0.05).
3. the effect of selective dopamine D4 receptor agonist ABT-724 on the expression of SHR cerebellar dopamine D4 receptor in.SHR cerebellar dopamine D4 receptor accumulative optical density (IOD) (2016900 + 494060) and mRNA expression (0.63 + 0.12) were significantly lower than WKY/SD rats (P 0.05), and the latter two had no significant difference in.ABT-724, middle, high dose and methylphenidate. The prognosis of SHR was significantly higher in cerebellar dopamine D4 receptor IOD and nRNA than in saline group (P 0.05).
[Conclusion]:
1. SHR young mice, as one of the most commonly used animal models of ADHD, compared with WKY and SD rats, showed obvious hyperactivity, impulsiveness, concentration of attention and cognitive dysfunction in the open test, Lat maze, and Morris water maze. This topic was based on the addition of another strain of rat (SD rat), the level of spontaneous activity of SHR. The selective attention and cognitive function were re tested and evaluated, which laid a theoretical foundation for further research.
The prognosis of 2. ABT-724 showed that SHR showed decreased white hair activity, cognitive function and non selective attention improvement, and the effect was similar to that of methylphenidate, suggesting that selective dopamine D4 receptor agonist ABT-724 could significantly improve the behavior cognition of SHR.
3. in the comparison of the expression of dopamine D4 receptor in the cerebellum of SHR/WKY/SD rats, the expression of dopamine D4 receptor in the brain region is significantly lower than that of the two control groups. This result provides a theoretical basis for further intervention test.ABT-724 to induce the increase of the expression of dopamine D4 receptor in the cerebellum of SHR rats, which is the same as that of methylphenidate, and the effect is similar to that of the methylphenidate. The appropriate stimulation of the dopamine D4 receptor agonist can increase the expression of the cerebellar dopamine D4 receptor at the same time in improving the cognitive activity of SHR, suggesting that the abnormal expression of the cerebellar dopamine D4 receptor may be related to the cognitive impairment of ADHD, and provides a theoretical basis for finding new therapeutic targets for ADHD.
【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：R749.94

【共引文献】