大鼠丘脑前核神经元内γ-氨基丁酸及其受体的表达

目的:探讨大鼠丘脑前核内γ-氨基丁酸(GABA)及其GABAA受体(GABAARα1和β2subunits)的表达,从形态学角度为系统研究丘脑前核的功能提供依据。方法:分别采用包埋后胶体金免疫电镜技术和原位杂交检测丘脑前核内GABA及GABAARα1和β2mRNA的表达。结果:(1)在丘脑前核,GABAARα1和GABAARβ2阳性神经元分布较密集,细胞形态较一致。空白对照切片为阴性,未见GABAARα1和GABAARβ2mRNA表达阳性神经元。(2)GABA胶体金免疫反应切片上,GABA胶体金颗粒浓重标记GrayⅡ型轴突终末,而树突、神经元、胶质细胞及背景标记极少。GABA能阳性轴突终末与中小型树突形成对称性轴-树突触,也与神经元胞体形成对称性轴-体突触。结论:提示在丘脑前核能够合成GABAARα1和GABAARβ2,且GABA能轴突终末与神经元的树突或胞体形成对称性突触。     

猫丘脑中央外侧核内脊丘系终末与丘脑-皮质投射神经元之间的突触联系

本实验应用顺行溃变和HRP逆行追踪相结合的方法，首次在电镜水平对猫丘脑中央外侧核内脊丘系终末与丘脑-皮质投射神经元之间的突触联系进行了研究．在脊髓第4颈段刀切损毁一侧侧索和前索后，将HRP注射于同侧大脑前上薛氏回和中上薛氏回前端。在电镜下于损毁同侧中央外侧核内可见下列突触连结：（1）溃变的脊丘系轴突终末与标记树突形成的轴-树突触；（2）溃变的脊丘系轴突终末与非标记树突形成的轴-树突触，个别非标记树突含有突触小泡；（3）正常的轴突终末与HRP标记树突和胞体形成的轴-树突触和轮一体突触；（4）正常的两个轴突终末与HRP标记树突形成的轴-轴-树连续性突触；（5）非标记的含突触小泡的突触前树突与HRP标记树突形成的树-树突触。同时可见大量汇聚型突触复合体。本文首次报道在丘脑中央外侧核内，脊丘系终末与丘脑-皮质投射神经元之间存在着直接的突触联系。     

猫三叉神经尾侧脊束核—丘脑—皮质通路在丘脑水平的突触联系

本文采用HRP逆行追踪与顺行溃变结合法对猫三叉神经尾侧脊束核-丘脑-皮质通路在丘脑腹后内侧核内的突触联系型式进行了研究。在电镜下发现,丘脑腹后内侧核內有五种突触联系形式:(1)溃变轴突终末与HRP标记树突形成轴-树突触;(2)溃变轴突终末与HRP标记的胞体形成轴-体突触,上述两类突触型式为该通路在丘脑水平的直接突触联系方式,此外尚有(3)溃变轴突终末与非HRP标记的树突形成的轴-树突触;(4)HRP标记树突与非溃变轴突终末形成轴一树突触;(5)HRP标记树突与非HRP标记的含有突触小泡的突触前树突形成的树-树突触。本文首次报道了三叉丘系纤维与丘脑皮质投射神经元间的直接突触联系方式为轴-树和轴-体突触。同时也发现了以树突为中心的突触复合体,它是该通路在丘脑水平的一个显著特点。     

迷走神经背核尾侧部内神经降压肽样免疫反应终末联系的电镜研究

用辣根过氧化物酶逆行标记法结合免疫细胞化学法(PAP法)对大鼠迷走神经背核尾侧部内神经降压肽样免疫反应终末的核内联系进行了电镜下的研究.发现少量神经降压肽样免疫反应轴突终末与HRP逆行标记的副交感节前神经元的树突构成非对称性突触;大多数神经降压肽样免疫反应轴突终末与未标记中间神经元的胞体和树突构成对称性或非对称性突触,以轴-树突触为主;未标记的轴突终末也可同HRP逆行标记的副交感节前神经元的胞体和树突构成对称性或非对称性突触.由此认为核内神经降压肽样免疫反应终末可通过直接或间接联系(后者为主)作用于副交感节前神经元,从而参与对内脏、心血管活动的调节.     

大鼠外侧膝状体背核的主要突触构筑

外侧膝状体背核(DLG)的突触构成成份主要来自视网膜、视皮质、丘脑网状核的轴突终末和DLG内神经元的突起。视网膜和视皮质来的轴突终末对DLG投射神经元和中间神经元的树突形成非对称性突触,丘脑网状核的轴突终末则对这两类神经元构成对称性突触,而中间神经元树突具有轴突样作用,对投射神经元树突形成对称性突触。这些结果有助于我们了解视觉信息在DLG内的加工处理过程。     

猫丘脑腹后外侧核内皮质—丘脑纤维终末与丘脑—皮质投射神经元之间的突触连接

用ＣＢ－ＨＲＰ逆行追踪与顺行溃变相结合的方法，对描丘脑腹后外侧核内的来自大脑皮质体感Ⅰ区的皮质—丘脑纤维终末与丘脑—皮质投射神经元之间的突触连接进行了电镜观察。向猫大脑皮质体感Ⅰ区内注射ＣＢ－ＨＲＰ５ｈ后，电解损毁原注射部位，术后动物存活４ｄ。电镜下发现丘脑瓜后外侧核内存在５种突触连接方式；（１）溃变的轴突终未与ＨＲＰ标记神经元胞体形成轴－体突触；（２）溃变的轴突终末与ＨＲＰ标记的树突形成轴—树突触；（３）溃变的轴突终末和其它突触前成分共同与中央树突形成汇聚型的突触复合体；（４）溃变的轴突终末与未标记树突形成的轴—树突触；（５）正常的轴突终末与ＨＲＰ标记神经元形成对称型的轴—体突触。     

大鼠延髓孤束核吻侧段内脑啡肽免疫阳性轴突末梢与含阿片μ受体的γ-氨基丁酸能神经元之间的突触联系

目的:观察大鼠孤束核吻侧段(rNTS)内脑啡肽免疫反应阳性(ENK-ir)终末、γ-氨基丁酸免疫反应阳性(GA-BA-ir)神经元及阿片μ受体免疫反应阳性(MOR-ir)神经元三者之间的联系。方法:包埋前免疫组织化学方法显色结合免疫金颗粒双重标记后,电镜观察。结果:在电镜下可见ENK-ir产物主要定位于圆形清亮突触小泡及大颗粒囊泡表面,GABA-ir产物主要分布于胞体及树突内部,多见于粗面内质网及核糖体等结构,MOR-ir产物主要位于树突膜、线粒体膜、内质网膜等结构表面;ENK-ir轴突终末与GABA-ir神经元胞体及树突之间形成对称性和非对称性的突触联系,以对称性突触为主;ENK-ir轴突终末与MOR-ir神经元的胞体及树突形成以对称性突触为主的突触联系;GA-BA-ir与MOR-ir产物共存于神经元内,GABA/MOR-ir神经元与免疫反应阴性的终末形成对称性和非对称性突触,以对称性突触为主。结论:rNTS内的ENK-ir终末可能通过与MOR结合,调节GABA能神经元的活性,从而参与味觉信息的感受和调节。     

猫颈外侧核内颈丘脑投射神经元的超微结构及其突触联系

猫颈外侧核接受来自同侧脊髓后角的脊颈束 ,其传出纤维投射至对侧的丘脑腹后外侧核。该通路与传导皮肤的伤害性信息有关。本文采用 HRP逆行追踪技术 ,在电镜水平研究了猫颈外侧核内颈丘脑投射神经元的超微结构及其突触联系。将 HRP注入猫左侧丘脑腹后外侧核 ,经颈总动脉灌流固定 ,TMB法呈色反应。选取右侧颈外侧核内有 HRP标记的细胞制备电镜标本 ,透射电镜观察。结果发现 ,颈外侧核内出现大、中型 HRP标记神经元 ,细胞核为卵圆形 ,可见核仁 ,胞浆丰富 ,含有多量的线粒体等细胞内器 ,HRP反应产物散在于其中。在颈丘脑投射神经元胞体的周围见有 HRP标记的树突以及非标记的轴突、神经元胞体及树突。 HRP标记的颈丘脑投射神经元作为突触后成分与其他成分形成轴 -树突触 ,轴 -体突触 ,轴 -轴 -体突触及轴 -树突触复合体。这些结果提示 :颈丘脑投射神经元接受广泛的传入联系     

猫丘脑腹后外侧核内皮质投射神经元超微结构及其突触联系——HRP法电镜研究

本文应用HRP逆行追踪法在电镜水平上对猫丘脑腹后外侧核内皮质投射神经元的超微结构及其突触联系进行了研究。该核内投射神经元超微结构特点为胞核较大,核仁清晰,核膜常有凹陷,常染色质较多,异染色质较少,胞浆丰富,含有大量的游离核糖体、粗面内质网及线粒体。标记的皮质投射神经元胞体和树突与非标记轴突形成轴-体突触和轴-树突触;标记树突还可以和突触前树突形成树-树突触,并做为中央树突参与形成汇聚型突触复合体。此外在标记的胞体与非标记的树突之间,标记的树突与非标记的树突之间,两标记的树突之间还存在着非突触丝状连接。     

大鼠杏仁体基底外侧核中含D2受体的γ氨基丁酸神经元受多巴胺能末梢支配(英文)

杏仁体中的多巴胺(DA)和γ -氨基丁酸(GABA)递质系统均参与精神分裂症的病理过程,临床上一般用多巴胺II型受体(D2)阻断剂予以治疗。然而,目前尚不清楚GABA与D2受体是否共存,也不清楚DA能神经末梢与GABA能神经元之间的联系方式。本实验用共聚焦激光扫描显微镜(CLSM)和免疫电镜(IEM)研究了杏仁体关键性核团基底外侧核中GABA与D2受体的共存关系以及DA神经能末梢与GABA能神经元之间的突触关系。CLSM显示由谷氨酸脱羧酶(GAD)标记的GABA能神经元全部对D2受体呈免疫阳性反应,表明GABA能神经元含有D2受体。IEM显示,在 980个DA能神经末梢形成的突触中,45%的突触是由DA免疫反应阳性神经末梢直接(36% )或间接(9% )与GAD免疫反应阳性神经元的树突形成,另 55%是由DA免疫反应阳性神经末梢与未标记的神经元成分形成。DA GABA的直接性突触进而可区分为单突触 (16% )、汇聚突触 (14% )及轴 轴突触(6% )。而DA- GABA的间接性突触是个突触复合体。在该复合体中,DA免疫反应阳性末梢在一个未标记的末梢上形成对称性突触,而该未标记末梢又与GAD免疫反应阳性树突形成非对称性突触。在DA与未标记神经元成分之间的突触中,AD免疫反应阳性末梢分别与未标记胞体(4% )、树突(42% )及轴突末梢(9% )形成突触。所有DA突触无一例外均为?     

Glutamatergic components of the retrosplenial granular cortex in the rat

The ultrastructural characteristics, distribution and synaptic relationships of identified, glutamate-enriched thalamocortical axon terminals and cell bodies in the retrosplenial granular cortex of adult rats is described and compared with GABA-containing terminals and cell bodies, using postembedding immunogold immunohistochemistry and transmission electron microscopy in animals with injections of cholera toxin- horseradish peroxidase (CT-HRP) into the anterior thalamic nuclei. Anterogradely labelled terminals, identified by semi-crystalline deposits of HRP reaction product, were approximately 1 microm in diameter, contained round, clear synaptic vesicles, and established asymmetric (Gray type I) synaptic contacts with dendritic spines and small dendrites, some containing HRP reaction product, identifying them as dendrites of corticothalamic projection neurons. The highest densities of immunogold particles following glutamate immunostaining were found over such axon terminals and over similar axon terminals devoid of HRP reaction product. In serial sections immunoreacted for GABA, these axon terminals were unlabelled, whereas other axon terminals, establishing symmetric (Gray type II) synapses were heavily labelled. Cell bodies of putative pyramidal neurons, containing retrograde HRP label, were numerous in layers V-VI; some were also present in layers I-III. Most were overlain by high densities of gold particles in glutamate but not in GABA immunoreacted sections. These findings provide evidence that the terminals of projection neurons make synaptic contact with dendrites and dendritic spines in the ipsilateral retrosplenial granular cortex and that their targets include the dendrites of presumptive glutamatergic corticothalamic projection neurons.     

Glutamatergic components of the retrosplenial granular cortex in the rat

The ultrastructural characteristics, distribution and synaptic relationships of identified, glutamate-enriched thalamocortical axon terminals and cell bodies in the retrosplenial granular cortex of adult rats is described and compared with GABA-containing terminals and cell bodies, using postembedding immunogold immunohistochemistry and transmission electron microscopy in animals with injections of cholera toxin- horseradish peroxidase (CT-HRP) into the anterior thalamic nuclei. Anterogradely labelled terminals, identified by semi-crystalline deposits of HRP reaction product, were approximately 1 m in diameter, contained round, clear synaptic vesicles, and established asymmetric (Gray type I) synaptic contacts with dendritic spines and small dendrites, some containing HRP reaction product, identifying them as dendrites of corticothalamic projection neurons. The highest densities of immunogold particles following glutamate immunostaining were found over such axon terminals and over similar axon terminals devoid of HRP reaction product. In serial sections immunoreacted for GABA, these axon terminals were unlabelled, whereas other axon terminals, establishing symmetric (Gray type II) synapses were heavily labelled. Cell bodies of putative pyramidal neurons, containing retrograde HRP label, were numerous in layers V–VI; some were also present in layers I–III. Most were overlain by high densities of gold particles in glutamate but not in GABA immunoreacted sections. These findings provide evidence that the terminals of projection neurons make synaptic contact with dendrites and dendritic spines in the ipsilateral retrosplenial granular cortex and that their targets include the dendrites of presumptive glutamatergic corticothalamic projection neurons.     

大鼠臂旁核内接受孤束核内脏传入之神经元同时接受中央杏仁核的反馈调节──溃变、HRP法结合包埋后免疫电镜研究

为研究来自孤束核的内脏传导信息在臂旁核水平是否接受中央杏仁核的反馈调节及其递质性质，以及孤束核—臂旁核—中央杏仁核传导通路中，在臂旁核水平是否接受ＧＡＢＡ的调节，本文将ＨＲＰ注入中央杏仁核进行顺、逆行标记，同时将兴奋性氨基酸毒素海人酸注入孤束核进行损毁，观实其顺行溃变终末，取外侧臂旁核超薄切片后结合抗ＧＡＢＡ的免疫电镜染色，观察发现有下列几种标记；（１）顺行溃变终末，所有的都与臂旁核神经元形成非对称性突触；（２）ＨＲＰ标记终末有两类：第一类和臂旁核神经元形成对称性突触，占ＨＲＰ标记终末总数的８０％以上，第二类与臂旁核神经元形成非对称性突触，另外有大量的ＨＲＰ标记的胞体和树突；（３）胶体金标记的ＧＡＢＡ阳性终末，皆与突触后结构形成对称性突触；（４）ＧＡＢＡ／ＨＲＰ双标记终末，具有ＧＡＢＡ免疫阳性终末和第一类ＨＲＰ标记终末的共同特征。上述几种标记在臂旁核内有以下几种关系：（１）溃变终末和ＧＡＢＡ阳性终末与同一个ＨＲＰ标记或非标记的突形成轴－树突触；（２）溃变终末和第一类ＨＲＰ标记终末共同终止于同一非标记讨突；（３）溃变终末与ＨＲＰ标记树突或胞位形成非对称性突触；（４）ＧＡＢＡ／ＨＲＰ双标记终末与非标记树突或胞体?     

猫后索核—丘脑—皮质通路在丘脑水平的突触联系

应用顺行溃变和ＨＲＰ逆行追踪相结合的方法对猫内侧丘系与丘脑皮质投射神经元在丘脑腹后外侧核内的突触联系组合型式进行了研究。电损毁一侧后索核后将ＨＲＰ注射于对侧皮质躯体感觉颈、躯干、四肢代表区，电镜下在注射区同侧的丘脑腹后外侧核内可见到下列七种突触形式；（１）溃变的内侧丘系轴突终末与ＨＲＰ标记树突形成的轴－树突触，较多；（２）溃变的内侧丘系轴突终末与ＨＲＰ标记的神经元体形成的轴－体突触较少；（３）溃变     

猫外侧颈核内脊颈纤维终末与颈丘脑投射神经元间的突触联系

本实验采用顺行溃变和ＨＲＰ逆行追踪结合的方法研究了猫脊颈丘脑通路在外侧颈核水平的突触联系。在脊髓颈段刀切损毁一侧背外侧索后将ＨＲＰ注射于对侧丘脑腹后外侧核。在电镜下于损毁同侧的外侧颈核内可见到下列突触联系：（１）溃变的轴突终末与ＨＲＰ标记的树突形成的轴—树突触；（２）溃变的轴突终末与标记的神经元胞体形成的轴—体突触；（３）溃变的轴突终末及正常的轴突终末与标记的中央树突形成的汇聚型突触复合体；（４）溃变的轴突终末与非标记的神经元树突和胞体形成的轴—树和轴—体突触；（５）正常轴突终末与标记的神经元树突和胞体形成的轴—树和轴—体突触。此外，在正常的神经元成分之间还可见到许多类型的突触。     

Ultrastructural subtypes of glutamate-immunoreactive terminals on rat trigeminal motoneurones and their relationships with GABA-immunoreactive terminals

 Electron-microscopic immunolabelling methods were used to study the relationships between glutamate-immunoreactive and γ-aminobutyric acid (GABA)-immunoreactive synapses on trigeminal motoneurones labelled by the retrograde transport of horseradish peroxidase. Serial sections were cut through the motor nucleus, alternate sections were incubated with antibodies to glutamate and GABA, and the immunopositive nerve terminal profiles were recognized using a quantitative, postembedding immunogold method. Boutons exhibiting high levels of glutamate immunoreactivity and GABA-immunoreactive boutons both formed axo-dendritic and axo-somatic synaptic contacts on labelled motoneurones. Boutons strongly immunopositive for glutamate were not immunopositive for GABA, and vice versa. Strongly glutamate immunoreactive boutons received axo-axonic synaptic contacts but did not form such contacts, while GABA-immunoreactive boutons formed axo-axonic synapses but did not receive them. The presynaptic elements at all axo-axonic synapses on to glutamate-immunoreactive boutons sampled were GABA-immunopositive. These data provide ultrastructural evidence in support of the roles of glutamate and GABA as transmitters at synapses on trigeminal motoneurones, and for presynaptic control of transmission at glutamatergic synapses by GABA acting at receptors at axo-axonic synapses. The vast majority (more than 90%) of strongly glutamate immunoreactive boutons contained spherical synaptic vesicles, in contrast to GABA-immunoreactive boutons, which contained pleomorphic vesicles. Most of the glutamate-immunoreactive boutons (67%) formed asymmetrical synaptic active zones, many of which (47% of total) were associated with subsynaptic dense ”Taxi” bodies (T-terminals), while a smaller population of boutons (21%) formed symmetrical synapses, and a few (11%) made synapses associated with subsynaptic cisternae (C-terminals). The heterogeneity of active zone ultrastructure of boutons identified as being glutamatergic on the basis of their high levels of immunolabelling is discussed in relation to possible differences in co-transmitters released, origins of the synaptic input or post-synaptic receptor subtypes activated. Received: 13 May 1996 / Accepted: 9 September 1996