慢性不可预见性应激大鼠海马喹啉酸对谷氨酸及其受体的调节

发布时间：2018-02-06 00:21

本文关键词： 抑郁海马 NMDA受体谷氨酸代谢型受体喹啉酸谷氨酸　出处：《陕西师范大学》2013年硕士论文　论文类型：学位论文

【摘要】：抑郁(depression)是一种伴随着高致残率、高死亡率,并且具有周期长、易反复等特点的疾病。随着社会压力增加,抑郁症患者数量日趋增长,该病给个人和社会带来的负担也随之加重。因此,尽快研究清楚抑郁发病机制就显得尤为重要。已有的研究证明,5-羟色胺(5-hydroxytryptamine,5-HT)在抑郁的发生中扮演着重要角色,临床对于抑郁症的治疗也是基于改善5-HT水平而进行,但5-HT失调并不能完全解释抑郁症的全部表现。研究发现应激使得海马谷氨酸(glutamic acid,Glu)释放量增加,其N-甲基-D-天冬氨酸(N-methyl-D-aspartic acid,NMDA)受体过度激活可能是抑郁发生原因之一,该受体拮抗剂具有显著的抗抑郁作用。此外,在应激性抑郁中代谢型谷氨酸受体mGluRl含量也增多,其拮抗剂AIDA同样能显著削弱由应激引起的抑郁样行为。喹啉酸(quinolinic acid, QUIN)是色氨酸代谢产物之一,在中枢神经系统中仅由小胶质细胞产生,它是NMDA受体的激动剂,与多种神经类疾病及神经退行性疾病都可能相关。有研究报道,抑郁症病人尿中促进QUIN产生的色氨酸代谢产物3-羟基犬尿氨酸(3-hydroxykynurenine,3HK)含量明显升高。由此推断,色氨酸代谢失调导致5-HT的下降和QUIN的升高很可能均与抑郁发生相关。在色氨酸代谢异常时,5-HT就会减少,而QUIN增加,QUIN不但可以过度激活NMDA受体和代谢型谷氨酸受体引起神经损伤,还能抑制胶质细胞对谷氨酸的重吸收及谷氨酰胺合成酶的表达,加剧中枢神经系统兴奋性毒的作用。然而,有关抑郁发生机制及治疗策略研究多集中于5-HT的变化,而对于QUIN在应激性抑郁发生中的作用及作用机制并不完全清楚。海马因其自身特点被广泛作为研究抑郁症的主要区域,但海马QUIN是否有参与应激性抑郁,它与Glu及其受体之间的关系并不清楚。为了探讨慢性应激性抑郁样行为发生过程中海马胶质细胞释放的QUIN的作用,以及它与Glu及其受体的关系,本研究通过建立慢性不可预见性温和应激(chronic unpredictable mild stress,CUMS)性抑郁模型,海马单侧微量注射QUIN,QUIN抑制剂Ro61-8048,NMDA受体拮抗剂MK-801和mGluRl拮抗剂AIDA,检测大鼠体重变化率,并通过糖水偏爱测试、旷场实验和悬尾实验等进行行为学表现测验,采用高效液相色谱法(high-performance liquid chromatography,HPLC)和酶联免疫吸附(enzyme linked immunosorbent assay,ELISA)法分别检测海马内Glu水平及其QUIN含量,运用Western blot方法检测NMDA受体和mGluRl的变化。研究结果如下： 1、CUMS诱发大鼠表现出明显的抑郁样行为,且海马Glu和QUIN含量、NMDA受体的NR2B亚基和mGluR1受体表达水平显著升高。 2、正常大鼠海马微量注射QUIN也表现出明显抑郁样行为,且Glu含量明显升高,NMDA受体的NR2B亚基和mGluRl表达水平显著升高。 3、CUMS诱发的抑郁样行为可被QUIN抑制剂Ro61-8048显著改善,且海马中Glu含量也显著降低,同时NMDA受体的NR2B亚基和mGluRl表达水平与CUMS(?)相比也明显降低。 4、CUMS引起的抑郁样行为可被海马注射NMDA受体拮抗剂MK-801和mGluRl拮抗剂AIDA显著改善,且其海马中Glu含量也明显降低,同时MK-801和AIDA对海马注射QUIN所引起的抑郁样行为也起到改善作用,并能降低由QUIN引起的Glu含量的升高。以上结果表明,CUMS引起海马小胶质细胞产生和释放QUIN增加,QUIN既可提高NR2B和mGluRl表达,也可以通过NMDA受体和代谢型谷氨酸受体途径使Glu含量增多,产生兴奋性神经毒,导致抑郁样行为发生。
[Abstract]:Depression (depression) is accompanied by a high morbidity, high mortality, and has a long cycle, easy to repeated and other characteristics of the disease. With the increasing social pressure, the growing number of patients with depression, the disease brought to the personal and social burden will be heavier. Therefore, it is particularly important to study the pathogenesis of depression is clear as soon as possible. Previous studies have demonstrated that serotonin 5- (5-hydroxytryptamine, 5-HT) plays an important role in the occurrence of depression in clinical treatment for depression, but also improve the level of 5-HT and 5-HT based, but can not fully explain the disorder of depression. The study found that all stress glutamate (glutamic acid, Glu) increased release of. The N- methyl -D- aspartate (N-methyl-D-aspartic acid, NMDA) receptor activation might be one of the reasons for depression, the receptor antagonists have remarkable antidepressant effect Use. In addition, in stress-induced depression of metabotropic glutamate receptor mGluRl content also increased, the antagonist AIDA can significantly weaken the depression like behavior caused by stress. Quinolinic acid (quinolinic acid QUIN) is one of the tryptophan metabolites in the central nervous system is only produced by microglia, it is NMDA receptor agonist, with a variety of neurological diseases and neurodegenerative diseases are likely related. Studies have reported that patients with depression and promote urinary tryptophan metabolites of 3- hydroxy kynurenic acid produced by QUIN (3-hydroxykynurenine, 3HK) was significantly increased. Thus, tryptophan metabolism disorder lead to elevated 5-HT drop and QUIN is likely to happen. And depression in abnormal tryptophan metabolism, 5-HT will be reduced, and the increase of QUIN, QUIN can not only excessive activation of NMDA receptors and metabotropic glutamate receptors induced by nerve injury, also The expression can inhibit the reabsorption of glutamine synthetase and glutamate on glial cells, increased central nervous system excitability toxicity. However, changes related to depression of mechanism and treatment strategy focused on 5-HT, and for QUIN in stress-induced depression in the role and the mechanism is not entirely clear.
The hippocampus is widely due to its own characteristics as the main research area of depression, but whether QUIN is involved in stress in hippocampus of depression and its relationship with Glu and its receptor is not clear. In order to investigate the release of hippocampal glial cells of chronic stress-induced depression like behavior during the process of the role of QUIN and its relationship with Glu and its receptor. In this study, through the establishment of chronic unpredictable mild stress (chronic unpredictable mild stress, CUMS) of hippocampus of depression model, unilateral microinjection of QUIN inhibitor, QUIN Ro61-8048, NMDA receptor antagonist MK-801 and mGluRl antagonist AIDA, weight change detection rate in rats, and the sucrose preference test, open field test and tail suspension test such behavior tests, using high performance liquid chromatography (HPLC high-performance liquid chromatography) and enzyme-linked immunosorbent assay (enzyme linked immunosorbent assay The level of Glu in the hippocampus and the content of QUIN were detected by ELISA). The changes of NMDA receptor and mGluRl were detected by Western blot. The results were as follows:
1, CUMS induced depressive behavior in rats, and the content of Glu and QUIN in the hippocampus, and the level of NR2B subunit and mGluR1 receptor expression of NMDA receptor significantly increased.
2, the microinjection of QUIN in the hippocampus of normal rats also showed significant depressive behavior, and the Glu content increased significantly, and the NR2B subunit and mGluRl expression level of NMDA receptor increased significantly.
3, CUMS induced depressive behavior can be significantly improved by QUIN inhibitor Ro61-8048, and the content of Glu in hippocampus is also significantly reduced. Meanwhile, the expression of NR2B subunit and mGluRl of NMDA receptor is also significantly lower than that of CUMS.
4, depression like behavior induced by CUMS can be injected into the hippocampus of NMDA receptor antagonist MK-801 and mGluRl antagonist AIDA significantly improved, and the content of Glu in the hippocampus were significantly decreased, while MK-801 and AIDA depression like behavior caused by QUIN injection into the hippocampus also play a role in improving, and can reduce the increase of Glu content caused by QUIN the.
The above results indicate that CUMS increases the production and release of QUIN from hippocampal microglia. QUIN can not only increase the expression of NR2B and mGluRl, but also increase Glu content through NMDA receptor and metabotropic glutamate receptor pathway, resulting in excitatory neurotoxicity, leading to depressive like behavior.

【学位授予单位】：陕西师范大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：R749.4

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