SYNAPTIC ULTRASTRUCTURE OF CAUDAL SPINAL TRIGEMINAL NUCLEUS IN RABBIT AND MOUSE

The caudal spinal trigeminal (CST) nucleus synapse consists of the pre- and postsynaptic mem branes and synaptic cleft. The active sites of the synapse consists of the presynaptic membranes. There are accumulated dense substances on the pre. and postsynaptic membranes, especially on the latter. Occasionally, subsynaptic cytoplasmic dense bodies ari: seen in the postsynaptic element, and intersynaptic filaments are found within the synaptic clefts. Synap- tic vesicles are located in the presynaptic terminals, Spherical, flat, granular and agranular synaptic vesi- cles are observed in presynaptic terminals. Numerous axon terminals, dendrites and axo dendritic, axosomatic, axoaxonic and dendrodendritic synapses were identified in the CST nucleus.. The dendrites were classified into type I (without synpatic vesicles) and type Il (few synaptic vesicles). Accord- iijg to the vesicle shape, the nuclear synapses are divided anto S (spherical), F (flat), S-F and F-S types. Anzong the observed synapses, about 20% were synaptic glomeruli. The functional significance of the synaptic pattem, glomeruli and vesicles in the CST nucleus are discussed.     

三叉旁核内含P物质的三叉神经初级传入终末的电镜研究

作用辣根过氧化物酶跨节追踪结合包埋后胶体金免疫电镜技术方法，对三叉旁核内含Ｐ物质的三叉神经初级传入终末形态和突触构筑进行了观察，这类终末大多较细，主要与树突和树突棘构成突触联系，另外，作还区分了三叉旁核内不含Ｐ物质的三叉神经初级传入终末以及含Ｐ物质的非三叉神经终末，上述结果提示三叉旁核可能感受与感合经不同类型终末传入的痛与非痛性感觉信息。     

Immunocytochemical localization of beta2-adrenergic receptors in the rat spinal cord and their spatial relationships to tyrosine hydroxylase-immunoreactive terminals

The distribution of beta2-adrenergic receptors (beta2-ARs) in the rat spinal cord was investigated by immunocytochemistry using an antibody against beta2-ARs. The relationship between beta2-ARs and catecholaminergic terminals containing the catecholamine synthesizing enzyme, tyrosine hydroxylase (TH), in the dorsal horn was also examined by light and electron microscopy. beta2-AR-immunoreactivity (beta2-AR-IR) showing the appearance of fibers and puncta was particularly dense in laminae I and II of the dorsal horn. Moderate immunoreactivity was observed in the intermediolateral cell column, in the ventral horn and around the central canal. Additional immunoreactivity was detected in ependyma lining the central canal. Capsaicin treatment reduced, but did not eliminate, the immunostaining in the dorsal horn. Double immunofluorescence histochemistry for beta2-AR and TH showed no colocalization of the two antigens. By electron microscopy, beta2-AR-IR was found in dendrites as well as unmyelinated axons and axon terminals which contained many small clear vesicles and several large granular vesicles. Such terminals usually formed asymmetric synapses on labeled or unlabeled dendrites. TH-labeled terminals were often near both axonal and dendritic profiles containing beta2-AR-IR and sometimes made synaptic contacts with beta2-AR-labeled dendrites. However, beta2-AR-IR was found on the extrasynaptic portion of the plasma membrane. No synaptic contact was made between TH-labeled terminals and beta2-AR-labeled varicosities. These results demonstrated that beta2-ARs are localized on both nociceptive primary afferents and on dendrites in the rat dorsal horn and provide the ultrastructural evidence that beta2-ARs on both axonal and dendritic profiles are activated by catecholamines released from catecholaminergic terminals via volume transmission.     

Trigeminal primary afferent terminals containing substance P－like immunoreactivity in the paratrigeminal nucleus

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猫丘脑腹后内侧核内皮质投射神经元的超微结构及突触联系

本文应用ＨＲＰ逆行追踪技术在电镜水平对猫丘脑腹后内侧核内投射神经元的超微结构及突触联系进行了研究。结果证明，该核内皮质投射神经元超微结构的特点为核较大，核膜常有凹陷，常柒色质较多，胞浆丰富，含有较多量的线粒体、粗面内质网及核糖体。标记的皮质投射神经元的树突主要作为突触后成分与轴突或突触前树突形成轴树突触或树树突触。此外，标记树突还可以作为中央树突参与形成树突型突触复合体。     

大鼠孤束核内含NT神经元的超微结构观察

用免疫电镜法对大鼠孤束核内侧亚核内NT-LI神经元的超微结构进行了观察。NT-LI产物可见于核周体、树突、轴突及终末内。标记轴突与树突构成轴-树突触最多见,轴-轴和轴-体突触少见。可见一些复合型突触和轴-树型自调节突触。此外一些NT-LI树突紧邻毛细血管。结果提示:(1)NT在孤束核调节心血管内脏活动中可能起着重要作用。(2)孤束核内NT神经元与血管之间可能存在神经-血管回路。     

RFWD2调控小鼠大脑皮层神经元树突发育及树突棘形成的功能效应

目的 探讨环指和色氨酸-天冬氨酸重复序列结构域2（RFWD2）差异表达对小鼠大脑皮层神经元树突发育及树突棘形成的功能效应。方法 利用免疫荧光鉴定RFWD2在小鼠全脑的定位及表达谱,通过RFWD2与神经元突触蛋白的共定位,明确其在神经元的细胞定位。通过电转染RFWD2-Myc过表达与shRNA载体,分析其对体外培养小鼠大脑皮层神经元树突发育、树突棘形成与突触功能的影响及作用机制。结果 RFWD2在小鼠大脑皮层与海马区均高表达,与突触形成具有明显的正相关性。RFWD2在神经元的突触前膜及后膜均有表达,与神经元树突的长度、分支数量与复杂性呈正相关。与对照组相比,RFWD2 过表达显著降低了神经元突触蛋白数量［突触小泡蛋白（SYN）4.5±1.2 vs 17.2±2.4/10 μm,P<0.01;突触后致密蛋白（PSD95）：2.1±0.3 vs 8.5±1.3/10 μm,P<0.01］;而RFWD2抑制表达显著增加了突触蛋白数量（SYN：19.6±2.6/10 μm,P<0.05;PSD95：11.5±1.1/10 μm,P<0.05）。与对照组和RFWD2过表达相比,RFWD2抑制表达降低了树突棘的数量（4.3±0.2 vs 6.2±0.5/10 μm,P< 0.05;4.3±0.2 vs 6.9±1.1/10 μm,P<0.01）。结论 RFWD2可通过Pea3家族成员与c-Jun的泛素化影响突触蛋白的表达,调控小鼠大脑皮层神经元树突发育、树突棘形成与突触功能效应,为后期作为靶点开展神经系统疾病的治疗奠定基础。     

皮质后索核投射纤维终末的超微结构和突触联系

本文采用顺行溃变法对猫后索核内皮质后索核投射纤维终末的超微结构和突触联系进行了研究。在电损毁皮质２～５天后，电镜下发现后索核内皮质后索核纤维终末存在三种溃变形式：即电子致密型、神经微丝型和电子透明型，以电子致密型最为多见。溃变的纤维终末常较粗大，主要含有大量密集的圆形突触小泡，主要与神经元的树突或胞体接触形成不对称型的轴－树突触、轴－轴突触、轴－体突触、轴－树－树系列突触，并参与形成以树突为中心的突触复合体。     

巨细胞旁(网状)外侧核神经元的Golgi法研究

应用改良的Golgi银浸法对大鼠巨细胞旁外侧核的细胞构筑学进行了研究。结果表明,大鼠巨细胞旁外侧核的神经元,根据其轴突是否伸至核外或进入邻近神经网丛分成长、短轴突两种。长轴突神经元根据树突有无棘,又分有棘长轴突、无棘长轴突神经元两种。短轴突神经元则分成:有棘短轴突;树突缺乏明显的棘但树突局部有明显膨大;树轴突区分不明显和树突或轴突末端形成网丛状分枝几种。     

扫描电镜下狗小脑皮质神经元的构筑及其联系

本文运用液氮冷冻断裂及扫描电镜研究狗小脑皮质神经元的构筑及其突触联系。在颗粒层中,卵圆形和圆形的颗粒细胞多聚集成簇,细胞表面粗糙不平并有无分支的线状轴突和具有爪状末梢的锥形树突。Golgi细胞位于颗粒细胞之间,它们形体较大,具有水平和上升的树突。苔藓纤维、颗粒细胞树突及Golgi细胞轴突之间形成突触联系,而且苔藓纤维与颗粒细胞树突之间有直接联系。在Purkinje层中清楚地显示出Purkinje细胞的三维构型。细胞体呈三角形或圆形,表面粗糙,细胞树突延伸至分子层。分子层中可见Purkinje细胞的二级和三级树突分支,平行纤维与Purkinje细胞棘形成突触。本文尚讨论了小脑皮质神经元构筑及其突触联系的机能意义。     

Ultrastructural characteristics of substance P-immunoreactive terminals in marginal division of rat striatum.

In our previous work using immunocytochemical method combined with tract tracing techniques a new subdivision was described in the striatum of the rat. This "marginal division" is more densely filled with substance P, enkephalin and dynorphin B terminals than the rest of the striatum. In the present study, the synaptic organization of the substance P immunoreactive (SPIR) terminals in the marginal division of the rat striatum was studied using electron microscopy and immunocytochemistry for substance P (SP). Four major types of SPIR synapses were identified in the marginal division: axodendritic, axospinous, axo-axonal, and compound synapses. Axodendritic and axospinous synapses, in which the postsynaptic targets were small or large dendrites or spines, were the most common. A few axo-axonic synapses were observed as were several subtypes of compound synapses with more than two synaptic components. SPIR axon terminals formed the presynaptic components of all these synaptic types, but in one case an unlabeled bouton was observed making a synaptic connection onto a SPIR dendrite. Both symmetric and asymmetric SPIR synapses were observed in the marginal division. The vesicles in the SPIR presynaptic boutons were mostly pleomorphic although a few of them were round. The existence of asymmetric synapses, round synaptic vesicles and small postsynaptic dendrites distinguishes the ultrastructure of the marginal division from that of the other parts of the striatum. The complex characteristics of the synaptic organization in the marginal division implies that the SPIR terminals in the marginal division originate from a different source than those in the rest of the striatum. The complexity of the synaptic organization further suggests that the function of the marginal division is different from that of the rest of the striatum.

     

大鼠脊髓前角运动细胞白质树突的电镜观察

在电镜下对未作标记及类霍乱原结合辣根过氧化物酶(CB-HRP)标记的大鼠脊髓运动细胞白质树突(WMD)进行观察,发现其全程上确有大量轴-树突触存在。突触小泡以清亮圆形和椭圆形为主,偶见有颗粒小泡与清亮小泡共存。此结果为脊髓运动细胞机能调节的旁侧回路假说提供了形态学依据。本文还就WMD传入联系的比较解剖学和可能的生理学特性,以及TMB电镜组织化学方法作了初步的讨论。     

大鼠纹状体边缘区内P物质阳性终末的突触特征

本文用免疫电镜方法研究了大鼠纹状体边缘区内P物质阳性终末的突触特征。边缘区内可见4种P物质免疫反应阳性(SPIR)的突触,即轴树、轴棘、轴轴和复合突触。轴树和轴棘突触较常见,轴轴突触和复合突触较少。轴树和轴棘突触的突触后靶区为小或大的树突或棘,复合突触含两种以上突触成份。在边缘区内可观察到对称型和非对称型两种突触。SPIR突触前终扣内的小泡大部分是多形性的,很少为圆形。这些突触特征均和纹状体其它部位不同,提示边缘区内SPIR终末的来源可能和纹状体其它部位不同,同时也说明边缘区的功能可能和纹状体其它区不同。     

内毛细胞带状突触结构及功能的研究进展

在视网膜及内耳的带状突触通过紧张性释放神经递质传导不同强度的光和声音信息。突触上的囊泡通过快速同步化机制和缓慢但持久的模式释放神经递质。带状突触是一个大的电子致密体,并在突触前膜集结大量的囊泡,其主要结构蛋白是RIBEYE。该骨架结构提供了带状突触-相关蛋白的锚定位置。带状突触具有胞吐、包吞、突触膜融合等功能。现对带状突触结构和功能的最新研究进展予以综述。     

大鼠孤束核内突触超微结构的衰老变化

在电镜下对3个月、12个月和25个月三组大鼠孤束核内侧亚核(mNTS)内突触超微结构的变化进行了定量研究。发现25个月组内mNTS神经毡中的突触密度、突触前轴突终末密度均较3个月和12个月组明显降低,含清亮囊泡伴大颗粒囊泡的突触前终末的构成比逐渐变小,而单纯含清亮囊泡的突触前终末的构成比则增大;但神经毡内线粒体密度、单个突触前轴突终末内的囊泡数、各型突触的构成比并无明显的变化。结果表明老年期大鼠mNTS内的突触有明显的衰老变化,这种衰老始于鼠龄1年以后,与该核功能的衰退有关。     

豚鼠星状神经节内P物质免疫反应纤维的超微结构和免疫反应性的定位

采用抗生蛋白链菌素-生物素-过氧化物酶复合物免疫组化技术,观察了豚鼠星状神经节内P物质(SP)-免疫反应(IR)纤维的超微结构和免疫反应性(IRy)的定位。IR无髓纤维包括非串珠和串珠部分.IRy主要定位于非串珠部分的运输颗粒内、串珠间段的胞浆内和串珠结构大核心囊泡的致密核心内。IR串珠结构与神经元的树突和胞体构成突触,串珠间段部分地暴露于组织间隙和(或)与其它神经元结构直接接触。这些表明,IR物质除突触释放外,还存在非突触弥散性释放.讨论了豚鼠星状神经节内SP-IR神经纤维的来源。     

后海穴区CB-HRP轴浆运输追踪的神经元节段性分布及相应运动神经无形态观察

用CB－HRP对大鼠后海穴区进行神经节段性分布的研究。在L6～S木水平标记出该穴相关运动神经元（Mn）的树突形成软膜下树突丛和空管膜下树突丛，两者均为嫌高尔基树突。有些远端树突穿越到对侧灰质。在背角和背连合核（DCN，S1～2）区域内CB-HRP标记的初级跨节感觉纤维和标记的前终末纤维可与送行标记的Mn树突汇聚和重叠。电针或免疫注射动物的Mn，其树突软膜下丛和室管膜下丛减少。结果提示后海穴区的神经支配在脊髓内形成传A-DCN整合-传出模式的神经反射回路，相关Mn（L6～S1）可能参与后海穴位作用。     

Morphological characteristics of the synaptic structures of substance P-immunoreactive terminals in the marginal division of the rat striatum

In the present study,the morphological characteristics of the synaptic structure(MCSS)of the substance P immunoreactive(SPIR)teminals in the marginal division(MrD)of the ratstriatum were studied by using electron microscopy and immunocytochemistry.Four major typesof SPIR symnapses were identified in teh MrD.axodendritic,axo-spinous,axo-axonic,and com-pound.Axo-dendritic and axo-spinous synapses were more common,and a few axo-axonic andcompound synapses wer observed as well.In the postsynaptic target zones of axo-dendritic,andaxo-spinous synapses,there were small or large dendrites or spires.Some synapses with morethan two synaptic components are referred to as compound synapses.Both symmetric andasymmetric SPIR synapses were seen in the MrD.The vesicles in the SPIR presynaptic boutonswere mostly pleomorphic although a few of them were round,The MCSS distinguishes theultrastructure of the MrD from that of the other part of striatum,which suggests that the func-tion of the MrD may be different from that of the rest of the striatum.     

银杏制剂对一侧迷路切除后前庭内侧核超微结构影响

目的 观察豚鼠一侧迷路切除（unilateral labyrinthectomy,UL）后前庭功能的恢复情况，前庭内侧核超微结构的变化及银杏叶标准提取物(standard extract of Gink-go biloba,EGb）金纳多对其的影响。方法 切除豚鼠左侧迷路，采用自然恢复和EGb给药两种处理，对比旋转后眼震与前庭内侧核超微结构变化的差别。结果 银杏叶标准提取物能明显促进一侧迷路切除后旋转后眼震的恢复，在超微结构方面，术后1wk，迷路切除（UL）组与迷路切除＋金纳多（UL＋EGb）组差别不明显；术后90d，UL组可见末梢突触增多，突触小泡密集，但神经元的突触结构未见增多；UL＋EGb组可见末梢与神经元突触结构均增多，突触小泡也明显增多。结论 银杏叶标准提取物能够促进前庭动态症状的恢复，恢复的发生可参与前庭区突触结构的增多、功能增强有关。