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D1R，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D1R，D2R基因表达的影响；用RNA酶保护实验检测43℃热损伤后D2RmRNA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。     

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.     

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。     

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。     

牛脑纹状体多巴胺D2受体的纯化

目的纯化牛脑纹状体多巴胺D2受体.方法以胆酸和氯化钠增溶纹状体膜制剂,以氟哌啶醇偶联的Sepharose 6B为亲和基质,用螺哌隆洗脱纯化D2受体.通过[3H]螺哌隆结合饱和实验和竞争实验测定其平衡解离常数(Kd)及配基结合特征.结果经一次亲和层析,D2受体被纯化约1 900倍,回收率约8.7%,比活性为168.7 pmol·mg-1,相对分子质量约94 000.通过Scatchard作图分析,纯化的受体kd为0.27nmol·L-1,并保持与D2受体的配基结合特征.结论以氟哌啶醇偶联的Sepharose 6B为亲和基质是纯化D2受体的有效方法.     

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。     

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。     

泌乳素腺瘤药物治疗耐药性的分子机制研究

泌乳素腺瘤是激素分泌性垂体腺瘤中最常见的一种,药物即多巴胺受体激动剂是首选的治疗方法,其中溴隐亭是代表性药物.泌乳素腺瘤的耐药性是多因素、多机制造成的,其直接原因是多巴胺D2受体数量下降,或受体亚型D2S/D2L的比例下降.而多巴胺D2受体水平下降的原因包括:mRNA交替剪接修饰缺陷、腺苷酸环化酶活性下降及D2R基因调控因子(如NGF水平)的影响等.     

Dopaminergic regulation of dopamine D3 and D3nf receptor mRNA expression

Dopamine D3 receptors have the highest dopamine affinity of all dopamine receptors, and may thereby regulate dopamine signaling mediated by volume transmission. Changes in D3 receptor isoform expression may alter D3 receptor function, however, little is known regarding coordination of D3 isoform expression in response to perturbations in dopaminergic stimulation. To determine the effects of dopamine receptor stimulation and blockade on D3 receptor alternative splicing, we determined D3 and D3nf isoform mRNA expression following treatment with the D3 receptor antagonist NGB 2904, and the indirect dopamine agonist amphetamine. Expression of tyrosine hydroxylase (TH) mRNA, the rate‐limiting enzyme in dopamine synthesis, was also determined. The D3/D3nf mRNA expression ratio was increased in ventral striatum, prefrontal cortex, and hippocampus 6 h following D3 antagonist NGB 2904 treatment, and remained persistently elevated at 24 h in hippocampus and substantia nigra/ventral tegmentum. D3 mRNA decreased 65% and D3nf mRNA expression decreased 71% in prefrontal cortex 24 h following amphetamine treatment, however, these changes did not reach statistical significance. TH mRNA expression was unaffected by D3 antagonist NGB 2904, but was elevated by amphetamine in ventral striatum, hippocampus, and prefrontal cortex. These findings provide evidence for an adaptive response to altered D3 receptor stimulation involving changes in D3 receptor alternative splicing. Additionally, these data suggest D3 autoreceptor regulation of dopamine synthesis does not involve regulation of TH mRNA expression. Finally, the observation of regulated TH mRNA expression in dopamine terminal fields provides experimental support for the model of local control of mRNA expression in adaptation to synaptic activity. Synapse, 2010. © 2010 Wiley‐Liss, Inc.     

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”。     

Differential regulation of striatal preproenkephalin mRNA by D1 and D2 dopamine receptors.

The effect of administration of subtype selective dopamine (DA) agonists on the 6-hydroxydopamine (6-OHDA) lesion-induced increase of striatal preproenkephalin (PPE) mRNA was examined by dot-blot hybridization. Eight days following a unilateral 6-OHDA lesion of the substantia nigra pars compacta (SNc), PPE mRNA levels in the ipsilateral striatum were increased approximately two-fold. Administration of the D2 DA agonist, quinpirole, dose-dependently attenuated the 6-OHDA lesion-induced increase in striatal PPE mRNA. The effect of quinpirole was blocked by coadministration of the D2 DA antagonist eticlopride. In contrast, administration of the D1 DA agonist, SKF 38393, either dose-dependently augmented or had no effect on the 6-OHDA lesion-induced increase in striatal PPE mRNA. In the contralateral striatum, administration of quinpirole decreased PPE mRNA, while administration of SKF 38393 increased PPE mRNA compared to sham lesioned control levels. These data suggest the action of DA at D1 and D2 DA receptors differentially regulates striatal PPE mRNA levels and the apparent inhibition of ENK biosynthesis by DA is mediated via an interaction with D2 DA receptors.     

High Abundance of GluR1 mRNA and Reduced Q/R Editing of GluR2 mRNA in Individual NADPH-Diaphorase Neurons

Striatal and cortical neurons containing NADPH-diaphorase [NADPH-d(+)] are highly vulnerable to excitotoxicity that is induced by activation of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)- or kainate-sensitive glutamate receptors. This has been attributed to Ca2+ entry through AMPA/kainate receptors in NADPH-d(+) neurons. In this study, we applied single cell RT-PCR technique to test the hypothesis that differences in levels and processing of the GluR2 subunit would contribute to the selective vulnerability of NADPH-d(+) neurons to AMPA. The nested PCR specific for GluR1-GluR4 showed that rat striatal NADPH-d(+) neurons expressed twice as much GluR1 mRNA as NADPH-d(-) neurons did. The percentage of RNA editing at the Q/R site of GluR2 was 46% in NADPH-d(+) neurons and 92% in NADPH-d(-) neurons. These results suggest that the unedited expression of GluR2 and the reduced ratio of GluR2/GluR1 render NADPH-d(+) neurons highly sensitive to Ca2+-mediated AMPA neurotoxicity. In support of this, most NADPH-d(+) neurons exposed to 100 microM AMPA showed Co2+ uptake and survived AMPA challenge only in the absence of extracellular Ca2+.     

Zur Röntgendiagnostik der Dünndarmstenosen

Ohne Zusammenfassung     

Localization of dopamine D3 receptor mRNA in the rat brain using in situ hybridization histochemistry: comparison with dopamine D2 receptor mRNA.

The messenger RNA (mRNA) of the recently characterized D3 dopamine receptor was visualized on rat brain sections using in situ hybridization with a 32P-labeled ribonucleic acid probe corresponding to a major part of the third cytoplasmic loop, a domain in which D2 and D3 dopamine receptors display little homology. For the purpose of comparison, D2 receptor mRNA was also specifically visualized on adjacent sections. The areas that expressed D2 and/or D3 receptors were also compared with those previously detected using [125I]iodosulpride, a ligand that binds to both D2 and D3 receptors with a similar affinity. The localization of D3 receptor mRNa markedly differs from that of D2 receptor mRNA. Whereas D2 receptor mRNA is expressed in all major brain areas receiving dopaminergic projections, particularly in the whole striatal complex, D3 receptor mRNA is expressed in a more restricted manner. It is mainly detected in telencephalic areas receiving dopaminergic inputs from the A10 cell group, e.g. accumbens nucleus, islands of Calleja, bed nucleus of the stria terminalis and other limbic areas such as the hippocampus and the mammillary nuclei. D2 and D3 receptor mRNAs were also detected at the level of the substantia nigra, suggesting that these receptors function as both autoreceptor and postsynaptic receptors. In several dopaminergic projection areas, e.g. ventral straitum, septal or mammillary nuclei, the distributions of D2 and D3 receptor mRNAs appeared complementary without overlap. The distribution of [125I]iodosulpride binding sites generally overlapped that of D2 or D3 receptor mRNAs, the latter being most abundant in dopaminergic areas known to be associated with cognitive and emotional functions.     

Elevation of D4 dopamine receptor mRNA in postmortem schizophrenic brain

The D₄ dopamine (DA) receptor has been proposed to be a target for the development of a novel antipsychotic drug based on its pharmacological and distribution profile. There is much interest in whether D₄ DA receptor levels are altered in schizophrenia, but the lack of an available receptor subtype-specific radioligand made this difficult to quantitate. In this study, we examined whether D₄ mRNA levels are altered in different brain regions of schizophrenics compared to controls. Ribonuclease protection assays were carried out on total RNA samples isolated postmortem from frontal cortex and caudate brain regions of schizophrenics and matched controls. ³²P-labelled RNA probes to the D₄ DA receptor and to the housekeeping gene, glyceraldehyde-3-phosphate dehydrogenase (G3PDH), were hybridised with the RNA samples, digested with ribonucleases to remove unhybridised probe, and separated on 6% sequencing gels. Densitometer analysis on the subsequent autoradiogams was used to calculate the relative optical density of D₄ mRNA compared to G3PDH mRNA. Statistical analysis of the data revealed a 3-fold higher level (P<0.011) of D₄ mRNA in the frontal cortex of schizophrenics compared to controls. No increase was seen in caudate. D₄ receptors could play a role in mediating dopaminergic activity in frontal cortex, an activity which may be malfunctioning in schizophrenia.     

Intrastriatal administration of botulinum neurotoxin A normalizes striatal D2R binding and reduces striatal D1R binding in male hemiparkinsonian rats

Cerebral administration of botulinum neurotoxin A (BoNT‐A) has been shown to improve disease‐specific motor behavior in a rat model of Parkinson disease (PD). Since the dopaminergic system of the basal ganglia fundamentally contributes to motor function, we investigated the impact of BoNT‐A on striatal dopamine receptor expression using in vitro and in vivo imaging techniques (positron emission tomography and quantitative autoradiography, respectively). Seventeen male Wistar rats were unilaterally lesioned with 6‐hydroxydopamine (6‐OHDA) and assigned to two treatment groups 7 weeks later: 10 rats were treated ipsilaterally with an intrastriatal injection of 1 ng BoNT‐A, while the others received vehicle (n = 7). All animals were tested for asymmetric motor behavior (apomorphine‐induced rotations and forelimb usage) and for striatal expression of dopamine receptors and transporters (D₁R, D₂R, and DAT). The striatal D₂R availability was also quantified longitudinally (1.5, 3, and 5 months after intervention) in 5 animals per treatment group. The 6‐OHDA lesion alone induced a unilateral PD‐like phenotype and a 13% increase of striatal D₂R. BoNT‐A treatment reduced the asymmetry in both apomorphine‐induced rotational behavior and D₂R expression, with the latter returning to normal values 5 months after intervention. D₁R expression was significantly reduced, while DAT concentrations showed no alteration. Independent of the treatment, higher interhemispheric symmetry in raclopride binding to D₂R was generally associated with reduced forelimb akinesia. Our findings indicate that striatal BoNT‐A treatment diminishes motor impairment and induces changes in D₁ and D₂ binding site density in the 6‐OHDA rat model of PD.