热损伤对大鼠纹状体多巴胺受体基因表达的影响

目的:研究热损伤对纹状体多巴胺受体D1 R,D2R基因表达水平以及D2R前体mRNA剪接的影响.方法:采用RT-PCR的方法分析43℃热损伤对大鼠纹状体多巴胺受体D1 R,D2R基因表达的影响;用RNA酶保护实验检测43℃热损伤后D2R mRNA剪接的变化.结果:43℃热损伤30min后,D1R表达量显著降低,D2R表达量升高.D2R长短片段D2RL/D2RS的比值较对照组明显升高,D2RL的转录占优势.结论:D1R,D2R及D2R长短片段比值变化结果为阐明热损伤的分子机制提供了实验依据.     

中脑腹侧区细胞移植对帕金森病鼠纹状体多巴胺受体敏感性的影响

大鼠纹状体中多巴胺受体介导的c-fos基因的表达与多巴胺D1受体的超敏现象有关。本实验将鼠胚胎中脑腹侧区细胞植入帕金森病大鼠模型纹状体后第12周,用免疫组化法检测阿朴吗啡诱发的c-fos蛋白,同时取相邻切片进行酪氨酸羟化酶检测。结果经图像分析发现胚胎中脑腹侧区移植,能显著减少移植侧纹状体中c-fos的表达量,说明胚胎中脑腹侧区细胞移植能够纠正多巴胺受体的超敏现象。     

多巴胺D1和谷氨酸NMDA受体参与调控异动症大鼠纹状体△FosB蛋白的表达

目的研究多巴胺D1和D2受体以及谷氨酸NMDA受体对△FosB蛋白表达水平的影响,由此探讨它们在左旋多巴诱导的异动症(Levodopa-induced Dyskinesia,LID)发病机制中的作用。方法对单侧黑质纹状体6-羟多巴胺(6-OHDA)损毁致帕金森病(PD)大鼠给予左旋多巴治疗28d制作LID模型,将大鼠分为7组:正常对照组、PD组、LID组、SCH23390治疗组、MK-801治疗组、raclopride治疗组和非LID组,分别观察各组行为学改变并进行异常不自主运动(abnormal involuntary movement,AI M)评分,用免疫组化和免疫印迹方法测定各组△FosB蛋白表达水平。结果多巴胺D1受体阻断剂SCH23390和谷氨酸NMDA受体阻断剂MK-801明显减轻LID大鼠行为学异常,而多巴胺D2受体阻断剂raclopride对异常不自主运动无明显影响;LID大鼠损毁侧纹状体△FosB蛋白表达较PD大鼠和非LID大鼠明显增加;与LID大鼠相比,MK-801和SCH23390均使△FosB蛋白表达显著下降,而raclopride没有这种效应;各组大鼠健侧纹状体△FosB蛋白表达水平没有显著差异。结论多巴胺D1受体和谷氨酸NMDA受体均通过参与调控纹状体△FosB蛋白的表达而影响大鼠LID的发生。     

吡贝地尔对帕金森病模型大鼠脑多巴胺D2受体的影响

目的研究常用抗帕金森药多巴胺受体激动剂吡贝地尔对脑多巴胺D2受体的影响。方法立体定位右侧纹状体注射6-羟多巴胺制备偏侧帕金森病大鼠模型,模型成功后予吡贝地尔灌胃治疗[30mg/(kg·d)]5周。分4组(正常组、术后4周帕金森病模型大鼠组、术后9周帕金森病模型大鼠经吡贝地尔治疗组、术后9周帕金森病模型大鼠未治疗组)行125I-依匹必利(125I-epidepride)大鼠脑多巴胺D2受体放射自显影。图像分析得到纹状体与小脑的平均光密度值,计算并比较各组左、右两侧脑多巴胺D2受体的特异性放射性摄取比值(纹状体/小脑-1)的变化。结果正常大鼠脑多巴胺D2受体对依匹必利的特异性放射性摄取比值左、右两侧差异无统计学意义;成为帕金森病模型后,右侧(损毁侧)比值较正常稍升高,但差异无统计学意义;未治疗组帕金森病模型大鼠双侧比值较刚成模型时均明显降低,右侧(损毁侧)比值仍较左侧高;经吡贝地尔治疗后,双侧比值较未治疗组进一步降低,右侧(损毁侧)降低甚,比值较左侧低。结论长期吡贝地尔治疗可能会使帕金森病模型大鼠双侧脑多巴胺D2受体的数量减少,损毁侧减少为甚。     

黑质纹状体多巴胺系统损伤后对大鼠纹状体SOM墓因转录神经元的影响

本实验用原位杂交组化和免疫组化方法研究了黑质纹状体多巴胺系统被６－羟基多巴胺损伤后对前脑ＳＯＭ神经元的影响。结果为损伤侧纹状体中ＳＯＭ神经元基因表达水平下降，但多肽合量无明显变化。结果提示黑质纹状体多巴胺神经系统在基因转录水平调节着纹状体中ＳＯＭ神经元的功能活动。     

胚胎黑质移植对帕金森病鼠纹状体中多巴胺受体敏感性的影响

大鼠纹状体中多巴胺受体介导的C－fos基因的表达与多巴胺D1受体的超敏现象有关。本实验在鼠胚胎黑质细胞植入帕金森病大鼠模型纹状体后第12周,用免疫组化法检测阿朴吗啡诱发的C－fos蛋白,同时取相邻切片进行酷氨酸羟化酶检测,结果经图像分析发现胚胎黑质移植,能显著减少移植侧纹状体中C－fos的表达量,说明胚胎黑质移植能够纠正多巴胶受体的超敏现象。除此之外,还发现C－fos减少的区域明显超过相邻切片酷氨酸羟化酶免疫阳性区域,表明细胞移植对超敏的多巴胺受体的影响范围大大超过了其诱发宿主残存多巴胺神经元再生的范围。     

多巴胺D2受体在垂体腺瘤中的表达及临床意义

目的垂体腺瘤约占颅内原发性肿瘤的10%~15%。多巴胺受体激动剂是治疗泌乳素(PRL)腺瘤的一线药物,并且对其它垂体腺瘤类型部分病例有效。研究表明:多巴胺受体激动剂是通过结合并激活多巴胺D2受体(D2R)发挥作用。本研究通过免疫组化的方法检测垂体腺瘤中D2R的表达情况。方法本研究所用197例垂体腺瘤标本均来自南京军区南京总医院神经外科手术病例。采用SP免疫组织化学染色法检测垂体腺瘤中D2R的表达。在光学显微镜下分析D2R在细胞中的定位及用半定量方法分析标本中阳性细胞的表达情况。免疫反应低表达定义为最终评分≤2分,高表达定义最终评分为>2分。结果 D2R定位于垂体腺瘤细胞胞浆。D2R在垂体腺瘤细胞中高表达率为65%,在PRL腺瘤和生长激素(GH)腺瘤的高表达率最高分别为为92.9%、90%;无功能性腺瘤(NFPA)D2R高表达率最低,仅为37.1%。D2R高表达率和垂体腺瘤的类型相关,与患者性别、肿瘤大小、肿瘤质地、侵袭性、是否复发或是否服用溴隐亭无显著相关性。结论 PRL腺瘤和GH腺瘤中D2R表达量高,适合多巴胺受体激动剂治疗;NFPA中D2R表达量低,不适合多巴胺受体激动剂治疗。     

抗帕Ⅰ号方剂对帕金森病大鼠纹状体多巴胺受体的影响

目的探讨抗帕Ⅰ号方剂对帕金森病(PD)大鼠纹状体多巴胺D1(DR1)、D2受体(DR2)表达的影响.方法 6-羟基多巴胺损毁制备偏侧PD大鼠模型,PD大鼠分为4组,分别进行抗帕Ⅰ号方剂、左旋多巴甲酯/苄丝肼、左旋多巴甲酯/苄丝肼/抗帕Ⅰ号方剂和生理盐水灌胃治疗4周,观察大鼠行为学变化;RT-PCR检测纹状体DR1、DR2受体的表达.结果抗帕Ⅰ号方剂联合左旋多巴治疗使PD大鼠产生稳定的对侧旋转行为;左旋多巴治疗后使PD大鼠在盐酸去水吗啡诱发后产生逐步增加的对侧旋转行为;联合抗帕Ⅰ号方剂及左旋多巴治疗可使盐酸去水吗啡诱发的对侧旋转次数减少.联合左旋多巴及抗帕Ⅰ号方剂治疗后损毁侧纹状体DR1 mRNA表达较对照组、抗帕Ⅰ号方剂组增强(P<0.05),而DR2 mRNA表达较对照组、抗帕Ⅰ号方剂组减弱(P<0.05).结论联合抗帕Ⅰ号方剂及左旋多巴治疗可改善PD大鼠行为学,但单独应用抗帕Ⅰ号方剂对多巴胺受体表达无明显影响,且抗帕Ⅰ号方剂无明显受体激动剂的作用.     

帕金森病大鼠模型尾壳核多巴胺D2受体活性变化研究

目的：探讨帕金森病病程中多巴胺D2受体的活性变化及其规律。方法：在建立6－羟基多巴胺毁损的帕金森病大鼠模型基础上，应用放射配基结合分析法结合Scanchard作图，测定不同时间点模型大鼠及对照大鼠尾壳核多巴胺D2受体的最大结合容量（Bmax)和平衡解离常数（KD）。结果：大鼠模型毁损侧尾壳核多巴胺D2受体Bmax显著升高，而KD值显著降低，在1个月时达到高峰，受体的亲合力显著增高。结论：帕金森病大鼠模型毁损侧尾壳核存在D2受体上行调节，D2受体明显超敏。     

黑质纹状体多巴胺系统损伤后对大鼠纹状体SOM基因转录神经元的影响

本实验用原位杂交组化和免疫组化方法研究了黑质纹状体多巴胺系统被６－羟基多巴胺损伤后对前脑ＳＯＭ神经元的影响。结果为损伤侧纹状体中ＳＯＭ神经元基因表达水平下降，但多肽含量无明显变化结果提示黑质纹状体多巴胺神经系统在基因围录水平调节着纹状体中ＳＯＭ神经元的功能活动。     

烟碱上调大鼠脑纹状体多巴胺D1受体mRNA表达诱导其行为改变

目的　 通过观察烟碱对大鼠脑纹状体D1,D2 受体mRNA表达的影响 ,研究烟碱诱导大鼠行为改变的可能机制 ,以进一步探讨烟碱对帕金森病具有保护效应的作用机理。 方法 SD大鼠 2 4只 ,随机分为生理盐水组(12只 )、烟碱组 (12只 )。分别给予生理盐水、烟碱 4mg/kg·d,2次 /d ,共 14d。每次注射药物后 0 .5h观察大鼠行为活动 ,并于末次注射药物后 0 .5h处死动物 ,快速分离纹状体 ,采用RT PCR方法检测大鼠纹状体D1,D2 受体mRNA的表达。结果 烟碱组大鼠于用药后第 3天 ,出现走动增多 ,易激惹 ,定型活动明显 ,并于第 714天达到高峰。在大鼠纹状体内 ,烟碱组D1受体mRNA表达比对照组上升 2 3% (分别为 98.6 3± 1.13,6 5 .2 9± 1.4 5 ,P <0 .0 1) ,两组D2 受体mRNA的表达无显著性差异 (P >0 .0 1)。 结论 烟碱可能通过上调大鼠纹状体D1受体mRNA的表达而诱导大鼠理毛、张口等行为改变 ;烟碱可能有部分D1受体激动样作用。     

电针后大鼠中枢多巴胺D1和D5受体mRNA的变化

应用原位杂交，放射自显影结合计算机图像处理技术检测电针（ＥＡ）后１０ｈ及２４ｈ时大鼠中枢多巴胺（ＤＡ）Ｄ１和Ｄ５受体信使ＲＮＡ（ｍＲＮＡ）的变化。结果显示，ＥＡ后１０ｈ脊髓Ｄ１和Ｄ５受体ｍＲＮＡ有明产高，２４ｈ时进一上不增高；而脑内Ｄ１和Ｄ５受体ｍＲＮＡ需至２４ｈ时才有显著增高，结果提示，在转录水平，ＥＡ可加强大鼠中枢Ｄ１和Ｄ５受体基因的表达，使这些受体合成增加。     

Differentiation of forebrain and hippocampal dopamine 1‐class receptors,D1R and D5R,in spatial learning and memory

Activation of prefrontal cortical (PFC), striatal, and hippocampal dopamine 1‐class receptors (D1R and D5R) is necessary for normal spatial information processing. Yet the precise role of the D1R versus the D5R in the aforementioned structures, and their specific contribution to the water‐maze spatial learning task remains unknown. D1R‐ and D5R‐specific in situ hybridization probes showed that forebrain restricted D1R and D5R KO mice (F‐D1R/D5R KO) displayed D1R mRNA deletion in the medial (m)PFC, dorsal and ventral striatum, and the dentate gyrus (DG) of the hippocampus. D5R mRNA deletion was limited to the mPFC, the CA1 and DG hippocampal subregions. F‐D1R/D5R KO mice were given water‐maze training and displayed subtle spatial latency differences between genotypes and spatial memory deficits during both regular and reversal training. To differentiate forebrain D1R from D5R activation, forebrain restricted D1R KO (F‐D1R KO) and D5R KO (F‐D5R KO) mice were trained on the water‐maze task. F‐D1R KO animals exhibited escape latency deficits throughout regular and reversal training as well as spatial memory deficits during reversal training. F‐D1R KO mice also showed perseverative behavior during the reversal spatial memory probe test. In contrast, F‐D5R KO animals did not present observable deficits on the water‐maze task. Because F‐D1R KO mice showed water‐maze deficits we tested the necessity of hippocampal D1R activation for spatial learning and memory. We trained DG restricted D1R KO (DG‐D1R KO) mice on the water‐maze task. DG‐D1R KO mice did not present detectable spatial memory deficit, but did show subtle deficits during specific days of training. Our data provides evidence that forebrain D5R activation plays a unique role in spatial learning and memory in conjunction with D1R activation. Moreover, these data suggest that mPFC and striatal, but not DG D1R activation are essential for spatial learning and memory. © 2015 Wiley Periodicals, Inc.     

Up-regulation of D3 dopamine receptor mRNA by neuroleptics

The effects of 14 days neuroleptic treatment on the expression of the D₃ dopamine receptor gene was investigated in rats using a sensitive polymerase chain reaction assay. In olfactory tubercle, D₃ mRNA levels increased following haloperidol (40%), pimozide (56%), and sulpiride (63%) administration, and in nucleus accumbens, levels increased after haloperidol (50%) and sulpiride (50%). D₃ expression in the motor striatum did not change with any antagonist tested. Clozapine did not affect D₃ expression in any brain region. These data suggest that dopamine antagonists can regulate the expression of the D₃ receptor in a brain region selective manner. The findings also suggest that the motor complications of chronic antipsychotic therapy are not due to D₃ receptor up-regulation in the striatum. (This article is a US Government work and, as such, is in the public domain in the United States of America.) © 1996 Wiley-Liss, Inc.     

Calcyon in the rat brain: cloning of cDNA and expression of mRNA

Calcyon is a 24 kD protein recently cloned from a human brain cDNA library and shown to interact with the dopamine receptor 1 (D1R) of D1-like receptors. This interaction shifts the effector coupling of D1R to stimulate a calcium signaling pathway, without influencing the D1R-adenylyl-cAMP pathway. To obtain more knowledge about the potential role of calcyon in the brain, we cloned rat calcyon cDNA and studied its distribution in the brain. Northern blot analysis and RT-PCR revealed that rat calcyon mRNA was expressed only in the brain. With the use of the in situ hybridization technique, we studied rat calcyon mRNA distribution in the brain and related it to the distribution of D1R and dopamine receptor 5 (D5R) mRNAs. Prominent calcyon mRNA signals were found in several brain regions, including hippocampus, hypothalamus, cerebellum, and medial prefrontal cortex. Less abundant calcyon mRNA expression was observed in the dorsal striatum region, where D1R mRNA is highly expressed and where D1R/cAMP-DARPP-32 signaling pathway is of great functional importance. The strongest expression of D5R mRNA was found in the hippocampus and cerebellum, where D1R mRNA expression was relatively low. In conclusion, rat calcyon appears to be a brain specific protein. There is a certain overlap between calcyon mRNA distribution and that of the D1R and D5 mRNAs, indicating that calcyon might be associated not only with D1R but also with D5R.     

Effects of septal nucleus lesion on dopamine D2 receptor expression in the prefrontal lobe, striatum, and brainstem in a rat model of schizophrenia★

BACKGROUND: It has been demonstrated that the septal nucleus is involved in the pathogenesis of schizophrenia. Based on autopsies of schizophrenia patients, studies have shown a reduced number of septal nucleus neurons and gila. In addition, experimental rat models of schizophrenia have shown increased dopamine receptor D2 binding sites in the basal ganglia, septal nuclei, and substantia nigra. Previous studies have demonstrated that the septal nucleus modulates dopamine metabolic disorder and dopamine D2 receptor balance.OBJECTIVE: Dopamine D2 receptor expression in a rat model of schizophrenia, combined with antipsychotic drugs, was analyzed in the prefrontal lobe, striatum, and brainstem. In situ hybridization was used to observe the effects of stereotactic septal nucleus lesions on dopamine D2 receptor expression in the brains of methylamphetamine-treated rats. DESIGN, TIME AND SETTING: A randomized, controlled, animal experiment was performed in the Laboratory of General Institute of Psychosurgery, Third Hospital of Chinese PLA from November 2005 to June 2006. MATERIALS: A total of 120 healthy, adult Sprague Dawley rats, weighing approximately 200 g, were included. Methylamphetamine (Sigma, USA) and an in situ hybridization detection kit for dopamine D2 receptor (Boster, China) were also used for this study. METHODS: All rats were randomly allocated to the following 4 groups, with 30 rats in each group: normal control, simple administration, septal nucleus lesion, and sham-operated groups. In the normal control group, rats were not administered or lesioned. In the remaining 3 groups, rats were intraperitoneally administered 10 mg/kg methylamphetamine, once per day, for 15 successive days to establish a schizophrenia model. Following successful model establishment, rats from the septal nucleus lesion group were subjected to stereotactic septal nucleus lesions. The cranial bone was exposed in rats from the sham-operated group, and the septal nucleus was not lesioned. MAIN OUTCOME MEASURES: At 7 days post-surgery, dopamine D2 receptor expression in the prefrontal lobe, striatum, and brainstem were detected by in situ hybridization. RESULTS: Dopamine D2 receptor expression in the rat prefrontal lobe, striatum, and brainstem was significantly higher in the simple administration group and sham-operated group, compared with the normal control group (P<0.01). In the septal nucleus lesion group, dopamine D2 receptor expression was significantly less than the simple administration and sham-operated groups, (P<0.01). There was no significant difference in dopamine D2 receptor expression between the simple administration and sham-operated groups (P>0.05). CONCLUSION: Septal nucleus lesions reduce dopamine D2 receptor expression in the prefrontal lobe, striatum, and brainstem in a rat model of schizophrenia, indicating that the septal nucleus modulates dopamine D2 receptor expression.     

慢性低灌注脑组织中NPY1受体mRNA的表达

目的:研究低灌注状态脑组织神经肽Y1受体的mRNA表达。方法:建立左侧颈外静脉与颈总动脉端侧吻合的大鼠模型,测定吻合形成后脑血流动力学及脑组织神经肽Y(NPY)改变,检测该组织NPY1R mRNA表达。结果:大鼠静脉动脉端侧吻合形成动静脉分流,左侧局部脑血流量显著降低,脑组织中NPY增加,NPY1R mRNA表达下降。吻合口阻断后,左侧大脑血流量显著增加,NPY1R mRNA表达进一步减低。结论:长期低灌注脑缺血后NPY1R减少,使脑血管自动调节功能下降导致“正常灌注压突破”。     

Polymorphisms of dopamine receptor and transporter genes and Parkinson's disease

Summary Disturbances of the dopamine system are involved in the pathogenesis of idiopathic Parkinson's disease (PD). Although genetic factors may play a role in the etiology of PD, there is little direct evidence implicating a specific gene. We conducted a study to test the hypothesis that allelic variations of the dopamine receptors (D2, D3, D4) and the dopamine transporter (DAT) contribute to the susceptibility to PD. Association analyses of 70 Japanese PD patients and the same number of age-matched controls did not reveal any association between alleles of the D2, D3 or D4 receptor genes or the DAT gene and PD. Thus, our results suggest that factor(s) other than allelic variations of these key proteins in the dopamine system contribute to the susceptibility to PD.     

Regulation of dopamine release and metabolism in rat striatum in vivo: Effects of dopamine receptor antagonists

1. 1. The acute effects of some of typical and atypical antipsychotic drugs on the dopamine release and metabolism in the dorsal striatum of freely moving rats were studied using transcerebral microdialysis technique.

2. 2. Classical neuroleptic drugs haloperidol (0.05, 0.1 and 0.2 mg/kg), thioproperazine (0.1, 0.2 and 0.4 mg/kg) and spiperone (0.02, 0.04 and 0.07 mg/kg) administered i.p. induced pronounced elevation of extracellular level of 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) up to 250–300 % to basal level while producing less increase in that of dopamine (DA) (up to 150–170 %).

3. 3. Atypical neuroleptics clozapine and thioridazine (both 2, 5 and 20 mg/kg) increased striatal DA release and DOPAC level approximately at the same degree (maximally up to 200% and 160%, respectively).

4. 4. Dopamine D3 receptor and autoreceptor preferring antagonists (+)-UH232 and (+)-AJ76 (both 4, 7 and 14 mg/kg) more potently increased DA release in comparison with DOPAC dialysate level ( (+)-AJ76 elevated DA level maximally up to 330 %, DOPAC - up to 250 %).

5. 5. The features of typical and atypical neuroleptics in preferential action on DA release or DOPAC output were observed in all doses of the drugs studied .

6. 6. The ability of the drugs to affect preferentially DA release or DOPAC extracellular level in rat striatum correlates to their relative affinities at D3 and D2 DA receptors.

7. 7. It is concluded that typical and atypical antipsychotic drugs might be clearly distinguished on the basis of their ability to affect preferentially DA synthesis/metabolism or release in rat dorsal striatum in vivo.

     

多巴胺受体的结构和功能

多巴胺是大脑中含量最丰富的儿茶酚胺类神经递质。多巴胺作为神经递质调控中枢神经系统的多种生理功能。多巴胺系统调节障碍涉及帕金森病，精神分裂症，Tourette综合征，注意力缺陷多动综合征和垂体肿瘤的发生等。本文综述了多巴胺受体的共同特征和各个受体的独特特征，以及它们在中枢神经系统的分布和功能，重点强调了多巴胺受体与学习记忆的关系。