红核与黑质的空间位置关系

本文将调查的41个成人整脑中的82个红核和82个黑质的空间形态与位置资料,通过还原、重建、重叠,获得二个核团的投影轮廓叠加图;并通过多元回归方程计算,绘画出二者在三个方位切面的三维空间回归平面图;从而进一步揭示三维切面上红核与黑质在空间的位置关系。     

大鼠侧脑室注射脂多糖选择性减少黑质神经生长因子的表达

目的:探讨脑内慢性炎症对大鼠黑质部位神经生长因子(nerve growth factor,NGF)表达的影响以及是否具有选择性。方法:将脂多糖(lipopolysaccharide,LPS)单次注入SD大鼠侧脑室制成脑内慢性炎症帕金森病(Parkinson's disease,PD)模型在注射后的各个时间点分离出不同部位的脑组织并提取蛋白,通过Western Blot方法检测NGF在黑质和中缝背核的表达变化。结果:Western Blot检测显示在LPS注射后4周开始黑质中NGF的蛋白表达降低,并显著低于对照组,一直持续到24周;而中缝背核中实验组NGF的表达与对照组相比一直没有显著性变化。结论:脑内慢性炎症可以选择性减少黑质中NGF的表达,提示可能与脑内慢性炎症选择性损伤黑质多巴胺能神经元相关。     

大鼠侧脑室注射脂多糖选择性减少黑质脑源性神经营养因子的表达

目的:探讨脑内慢性炎症对大鼠黑质部位脑源性神经营养因子(BDNF)表达的影响以及是否具有选择性。方法:将脂多糖(LPS)单次注射入SD大鼠侧脑室,造成全脑慢性炎症帕金森病(PD)模型,在注射后的不同时间点分离出不同部位的脑组织并提取蛋白,通过Western Blot方法检测BDNF在黑质和皮层的表达。结果:LPS注射后1周时黑质中BDNF的蛋白表达显著低于对照组,2周和4周时无显著差异,从8周开始显著低于对照组并且一直持续到24周;而皮层中实验组BDNF的表达与对照组相比在2周、4周、12周和24周时显著升高。结论:脑内慢性炎症选择性、进行性减少黑质中BDNF的表达,提示可能与脑内慢性炎症选择性、进行性损伤黑质多巴胺能神经元相关。     

鱼藤酮对大鼠脑内代谢型谷氨酸受体1α表达的影响

目的:观察鱼藤酮对大鼠脑内代谢型谷氨酸受体(mGluR)1α表达的影响.方法:利用背部皮下注射鱼藤酮制备大鼠帕金森病模型,以免疫组织化学方法显示mGluR1α在大鼠脑内的免疫反应强度.结果:与对照组相比,鱼藤酮组大鼠尾壳核酪氨酸羟化酶(TH)免疫反应强度明显降低、黑质TH阳性神经元数目减少;尾壳核、内侧苍白球、外侧苍白球以及黑质网状部的mGluR1α免疫反应强度呈现不同程度的减弱,以黑质网状部降低最明显;内侧苍白球、外侧苍白球及黑质网状部mGluR1α免疫反应阳性突起减少;mGluR1α灰度值结果分析显示鱼藤酮组与对照组差异有统计学意义.结论:鱼藤酮降低大鼠脑内mGluR1α的表达.     

胎脑黑质脑内移植反转PD鼠纹状人NPY和D2R mRNA过度表达

为研究胎脑黑质脑内移植对帕金森氏病大鼠纹状体内神经肽Ｙ及多巴胺Ｄ２型受体ｍＲＮＡ表达的影响。本文采用核酸斑点杂交方法对胎脑黑质脑内移植前后的帕金森氏病大鼠纹状体内神经肽Ｙ及多巴胺Ｄ２型受体ｍＲＮＡ含量进行了连续定量地观察，研究发现胎脑黑质移植物不仅能纠正帕金森氏病大鼠的行为异常，而且还能彻底反转帕金森氏病大鼠纹状体内因去神经支配造成的神经Ｙ及多巴胺Ｄ２受体ｍＲＮＡ过度表达，研究结果提示胎脑黑质移植     

胚胎神经上皮干细胞脑内移植治疗大鼠帕金森病

背景：研究表明胚胎干细胞移植可改善血管性痴呆大鼠的学习记忆功能,增强神经的可塑性,诱导自身定向迁移并分化为成熟神经元。 目的：观察胚胎神经上皮干细胞脑内移植治疗帕金森病大鼠及移植细胞的迁徙情况。 方法：将绿色荧光蛋白转基因鼠的胚胎神经上皮干细胞分别移植到帕金森病大鼠的黑质、纹状体和侧脑室内,移植后检测移植细胞的存活、迁徙与分化;利用高效液相色谱法检测实验动物脑内多巴胺神经递质的含量;对比实验动物旋转行为的改变,评估胚胎神经上皮干细胞移植对帕金森病大鼠的治疗作用。 结果与结论：移植细胞存活良好且分化出了酪氨酸羟化酶阳性细胞,向黑质纹状体环路迁徙趋势明显;脑内多巴胺含量增加,动物旋转行为改善明显。表明移植到帕金森病大鼠脑内的神经上皮干细胞多向黑质纹状体环路迁徙,且可增加脑内多巴胺神经递质的含量治疗帕金森病。中国组织工程研究杂志出版内容重点：干细胞;骨髓干细胞;造血干细胞;脂肪干细胞;肿瘤干细胞;胚胎干细胞;脐带脐血干细胞;干细胞诱导;干细胞分化;组织工程全文链接：     

多巴胺受体与药物作用

一、绪论 (一)多巴胺(儿茶酚乙胺)(Dopamine;DA) 过去认为,多巴胺只是去甲肾上素(NE)合成时的中间体;但脑内DA与NE的分布并不一致。如哺乳类动物脑中DA有80％集中在黑质-纹状体,以尾核和壳核尤多。其DA:NE约为100∶1。而且纹状体中之DA主要含于突触体部分,提示DA可能有突触传递功能;后来发现刺激黑质可引起尾核内DA释放,从而证实黑质中有DA能神经元。其后,又证明中脑-边缘系统、丘脑下部以及交感神经节中也有DA能神经元。所以,DA本身就是一种神经递质。 为了便于说明问题,首先复习一下多巴胺的合成、储存、释放、降解等生物代谢过程。     

成年大鼠脑内ATP敏感性钾通道亚型mRNA表达的研究

为探讨ATP敏感性钾通道(KATP)亚型在大鼠脑组织中的表达,本研究采用半定量逆转录聚合酶链反应 (RT PCR)检测了大鼠小脑、大脑皮质、海马、纹状体、黑质的KATP亚型mRNA的表达。结果显示Kir6. 1、Kir6. 2、Sur1、Sur2B在小脑、大脑皮质、海马、纹状体、黑质中均有表达,Sur2A在脑组织中未见表达。Kir6. 1mRNA在海马和黑质的相对表达水平明显高于小脑、大脑皮质和纹状体(P<0.01);Kir6. 2和Sur1mRNA在黑质的相对表达水平明显高于小脑、大脑皮质、海马和纹状体 (P<0.01 );Sur2BmRNA在黑质、海马和纹状体的相对表达水平明显高于小脑和大脑皮质(P<0.01 )。以上结果提示KATP在脑内具有广泛表达,其表达水平在不同部位存在着差异性。     

脑内主要神经核团三维空间的定位及其临床意义

目的：对脑内主要神经核团进行定位研究，为脑立体定向手术提供解剖学基础。方法：对１０２个整脑作三维切面的２ｍｍ厚连续切片，分别对８２个红核、黑质、丘脑底核，１１０个杏仁核、１２２个豆状核（壳核、苍白球）、丘脑和１１４个尾状核头等脑内主要神经核团进行定位研究。结果：各神经核团三轴“靶心”坐标值以及与大脑原点的位置关系。上述核团全部位于原点外，红核１００％位原点下、７６．８％位原点后，黑质１００％位原点下、６４．６％位原点前，丘脑底核１００％位原点下、４３．５％位原点前，杏仁核全部位原点前、下，壳核７６．６％位原点前、６９．２％位原位点，苍白球７６．１％位原点前、５８．９％位原点上，丘脑６１％位原点后、８９．５％位原点上，尾状核头１００％位原点前，８０％位原点上。结论：脑内主要神经核团的空间位置结果对脑的立体定向手术有参考价值     

胎脑黑质脑内移植反转PD鼠纹状体内NPY和D_2R mRNA过度表达

为研究胎脑黑质脑内移植对帕金森氏病大鼠纹状体内神经肽Ｙ及多巴胺Ｄ２型受体ｍＲＮＡ表达的影响，本文采用核酸斑点杂交方法对胎脑黑质脑内移植前后的帕金森氏病大鼠纹状体内神经肽Ｙ及多巴胺Ｄ２型受体ｍＲＮＡ含量进行了连续定量地观察，研究发现胎脑黑质移植物不仅能纠正帕金森氏病大鼠的行为异常，而且还能彻底反转帕金森氏病大鼠纹状体内因去神经支配造成的神经肽Ｙ及多巴胺Ｄ２受体ｍＲＮＡ过度表达，研究结果提示胎脑黑质移植物对宿主纹状体形成的神经再支配可能是促使这两种物质基因表达正常化的主要原因。     

Time-course and localization of transferrin receptor expression in the substantia nigra of 6-hydroxydopamine-induced parkinsonian rats.

Parkinson's disease is a neurodegenerative disease characterized by dopaminergic cell death in the substantia nigra. The cause of the cell death is, however, obscure. Recently, accumulation of iron in the parkinsonian substantia nigra and iron-catalysed free radical generation have been proposed as possible causes of nigral cell death. The transferrin receptor has been implicated as a possible mediator of this iron accumulation in the parkinsonian substantia nigra. The present study investigated the distribution of transferrin receptor-immunoreactive proteins and its co-localization with tyrosine hydroxylase in the normal rat substantia nigra and their expressions in the parkinsonian substantia nigra from three days to three months after 6-hydroxydopamine lesioning. Computer image analysis of the grey mean of transferrin receptor staining in the microvessels was also employed. The results showed that the transferrin receptor immunolabelling was localized in some neurons and glial cells in the normal substantia nigra pars compacta and pars reticulata, and that about 54% of tyrosine hydroxylase-positive cells were also stained with transferrin receptor. There was a decrease of tyrosine hydroxylase- and transferrin receptor-positive cells in the 6-hydroxydopamine-lesioned substantia nigra. The grey mean of transferrin receptor staining in microvessels in the lesioned substantia nigra was, however, not different from that in the control. It was concluded that transferrin receptors in neurons, glial cells and microvessels might not be responsible for iron accumulation in the parkinsonian substantia nigra. The loss of transferrin receptor-immunopositive cells might, however, partly be accounted for by the death of transferrin receptor-positive dopaminergic cells induced by 6-hydroxydopamine lesioning.     

Activation of metabotropic glutamate receptor 1 inhibits glutamatergic transmission in the substantia nigra pars reticulata

The substantia nigra pars reticulata is a primary output nucleus of the basal ganglia motor circuit and is controlled by a fine balance between excitatory and inhibitory inputs. The major excitatory input to GABAergic neurons in the substantia nigra arises from glutamatergic neurons in the subthalamic nucleus, whereas inhibitory inputs arise mainly from the striatum and the globus pallidus. Anatomical studies revealed that metabotropic glutamate receptors (mGluRs) are highly expressed throughout the basal ganglia. Interestingly, mRNA for group I mGluRs are abundant in neurons of the subthalamic nucleus and the substantia nigra pars reticulata. Thus, it is possible that group I mGluRs play a role in the modulation of glutamatergic synaptic transmission at excitatory subthalamonigral synapses. To test this hypothesis, we investigated the effects of group I mGluR activation on excitatory synaptic transmission in putative GABAergic neurons in the substantia nigra pars reticulata using the whole cell patch clamp recording approach in slices of rat midbrain. We report that activation of group I mGluRs by the selective agonist (R,S)-3,5-dihydroxyphenylglycine (100 microM) decreases synaptic transmission at excitatory synapses in the substantia nigra pars reticulata. This effect is selectively mediated by presynaptic activation of the group I mGluR subtype, mGluR1. Consistent with these data, electron microscopic immunocytochemical studies demonstrate the localization of mGluR1a at presynaptic sites in the rat substantia nigra pars reticulata.From this finding that group I mGluRs modulate the major excitatory inputs to GABAergic neurons in the substantia nigra pars reticulata we suggest that these receptors may play an important role in basal ganglia functions. Studying this effect, therefore, provides new insights into the modulatory role of glutamate in basal ganglia output nuclei in physiological and pathophysiological conditions.     

Dopamine release from the rat substantia nigra in vitro. Effect of raphe lesions and veratridine stimulation

In order to eliminate the 5-hydroxytryptaminergic input to the substantia nigra lesions were placed in the dorsal and medial raphe nuclei in a number of rats. The release of exogenously applied [³H]dopamine from the partially denervated substantia nigra was determined in vitro and found to be very similar to the release observed from slices of control substantia nigra. These results lend further support to the theory that the release of exogenously applied [³H]dopamine at the level of the substantia nigra occurs mainly from dopaminergic dendrites, rather than from terminals of 5-hydroxytryptamine-containing neurons.A veratridine-induced release of [³H]dopamine from the pars reticulata of the substantia nigra is also described. An almost complete blockade of veratridine (3.0 μM) stimulation was observed with 100 nM tetrodotoxin. Similar effects of veratridine and tetrodotoxin were also observed on [³H]dopamine release from slices of corpus striatum. These results suggest that dendrites of the dopaminergic neurones in the substantia nigra contain fast, tetrodotoxin-sensitive sodium channels.     

新生大鼠大脑皮质、纹状体及中脑黑质器官型脑片培养

目的探索大脑皮质、纹状体及黑质密部器官型脑片的体外培养。方法选出生2d内的W istar乳鼠,取大脑皮质、纹状体及黑质致密部,切成300μm厚的脑片,共同转至带有M illicell微孔膜插件的培养皿中。分别培养0d、10d、20d和30d,倒置显微镜观察,酪氨酸羟化酶(TH)免疫荧光染色及激光共聚焦显微镜下检测脑片摄取溴化已啶(EB)能力。结果黑质密部多巴胺能神经元(TH阳性)及突起逐渐长入纹状体中,约20d左右,纹状体及黑质致密部脑片长在一起,脑片中所有细胞EB染色呈阴性,说明无坏死细胞。培养30d时,脑片约10%神经元呈EB染色阳性,细胞变性坏死。结论培养20d内脑片已经形成多巴胺能神经元从黑质密部到纹状体通路,可用于帕金森病等神经退行性疾病研究的组织模型。     

Endogenous dopamine modifies electroresponsiveness of pars compacta cells in the guinea pig substantia nigra in vitro

Summary In the nigrostriatal pathway, dopamine is released not only from striatal nerve terminals, but also locally from the dendrites of nigrostriatal neurones within the substantia nigra itself. Exogenous dopamine is known to inhibit the firing of these neurones when applied directly to the substantia nigra in micromolar concentrations: but the amounts used are probably much higher than the endogenous concentration of the transmitter. Moreover, the direct, local blockade of nigral dopamine autoreceptors has not been reported to affect the firing rates of these neurones. The electrophysiological effects of endogenous dopamine were therefore examined using intracellular recordings from the substantia nigra in vitro. When slices of the midbrain were pharmacologically depleted of endogenous dopamine, selective membrane properties of nigrostriatal neurones were altered in a manner consistent with the effects of the exogenous transmitter. Similar changes were observed in control slices on exposure to the dopamine antagonist haloperidol. It is concluded that endogenous dopamine normally exerts a tonic influence on the electrical properties of nigrostriatal neurones.     

Dopamine-regulated phosphorylation of synaptic vesicle-associated proteins in rat neostriatum and substantia nigra

Dopamine, acting through dopamine D1 receptors and cyclic AMP-dependent protein kinase, has been found to increase the state of phosphorylation of the synaptic vesicle-associated phosphoproteins synapsin I and protein III in slices of rat neostriatum and substantia nigra. In the neostriatum, the effect of dopamine was mimicked by SKF 38393, a D2 receptor agonist, and was abolished by preincubation of the slices with fluphenazine or SCH 23390, antipsychotic drugs which are potent D1 receptor antagonists, but not by the D2 receptor antagonists l-sulpiride or spiroperidol. The maximal effect of dopamine in the neostriatum represented approximately 30-35% of the maximal effect induced by 8-bromo cyclic AMP, suggesting that a similar fraction of nerve terminals in the neostriatum may express the dopamine D1 receptor. Evidence for a small population of beta-adrenergic receptors regulating nerve terminal protein phosphorylation in the neostriatum, distinct from the D1 dopamine receptors, was also obtained. In the substantia nigra, the effect of dopamine also appeared to be mediated through a D1 dopamine receptor, since it was abolished by fluphenazine and SCH 23390. The maximal effect of dopamine in the substantia nigra represented approximately two-thirds of the effect induced by 8-bromo cyclic AMP, suggesting that a similar fraction of nerve terminals in the substantia nigra may express the dopamine D1 receptor. The ability of dopamine D1 receptor activation to stimulate both synapsin I and protein III phosphorylation and GABA release in both the neostriatum and substantia nigra may be causally linked.     

大鼠中脑黑质致密部突触构筑的研究

本研究采用透射电镜方法对黑质致密部的突触类型进行详细观察。结果表明,黑质致密部虽以轴—树突触为主,但轴—树—轴突触的数量明显增多,并可观察到并列突触。对结果的讨论提示:致密部不同类型突触是黑质执行其重要调控功能的保证,而并列突触很可能是神经回路中易化过程的基本结构。     

ARPP-21, a cAMP-regulated phosphoprotein enriched in dopamine-innervated brain regions: tissue distribution and regulation of phosphorylation in rat brain

ARPP-21 (cAMP-regulated phosphoprotein, Mr = 21,000 as determined by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate), a phosphoprotein substrate for cAMP-dependent protein kinase, is unevenly distributed in adult rat brain. Using immunoblotting and phosphorylation in vitro followed by immunoprecipitation, ARPP-21 was found to be enriched in caudate-putamen, substantia nigra, nucleus accumbens and olfactory tubercle. Intermediate levels were found in cerebral cortex and hippocampus. ARPP-21 was very low in most other brain areas and was not detected in any of the peripheral tissues studied. Following unilateral lesion of the caudate-putamen with quinolinic acid, a marked decrease in the levels of ARPP-21 was observed in both the lesioned caudate-putamen (-75%) and the ipsilateral substantia nigra (-70%) compared with the unlesioned side. This result demonstrates the enrichment of ARPP-21 in striatonigral neurons. In slices of caudate-putamen, substantia nigra or cerebral cortex incubated in vitro, the phosphorylation of ARPP-21 was enhanced by 8-Br-cAMP, a stable analog of cAMP. In striatal slices, forskolin, a compound which stimulates adenylate cyclase directly, enhanced the phosphorylation of ARPP-21 with an EC50 of 0.5 microM. In conclusion, ARPP-21 is a neuron-specific phosphoprotein enriched in specific brain areas which are known to receive a rich dopaminergic innervation and to contain high levels of D1 dopamine receptors. The phosphorylation of ARPP-21 is likely to mediate some of the intracellular effects of neurotransmitters which stimulate adenylate cyclase in these regions, in particular dopamine and vasoactive intestinal peptide.     

Corticonigral projections from area 6 in the raccoon

Summary The corticonigral projections from area 6 in the raccoon were investigated using the autoradiographic tracing method. Injections of tritiated proline and leucine were made into either medial or lateral area 6 subdivisions. Uniformly distributed silver grains were observed overlying the ipsilateral substantia nigra pars compacta (SNc) while more restricted foci of label indicative of fiber labeling were present in the substantia nigra pars reticulata (SNr). Autoradiographic label was also present in the substantia nigra pars lateralis (SNl), the retrorubral area and the ventral tegmental area of Tsai. The existence of corticonigral projections from area 6 may serve to modulate SNc activity as a whole and provide an important substrate for the cerebral control of movement.Abbreviations cp cerebral peduncle - IP interpeduncular nucleus - PG pontine gray - R red nucleus - RR retrorubral area - SNc substantia nigra, pars compacta - SNl substantia nigra, pars lateralis - SNr substantia nigra, pars reticularis - VTA ventral tegmental area