胚胎与成人三叉神经节细胞形态对比观察*

摘要目的：探讨胚胎与成人三叉神经节细胞的形态学特征。方法：采用常规HE 染色,运用电子显微超微结构技术及特殊染色,对 比观察二者的形态学特征。结果：胚胎与成人三叉神经节细胞大体分布及形态一致,与胚胎三叉神经节细胞相比,成人最突出的 特点是节细胞大,核仁清晰,居中。电镜下节细胞的细胞器较丰富,发育完善。且成人三叉神经节神细胞明暗区别明显。结论：三 叉神经节细胞结构与功能完善是在成年之后,成人三叉神经节细胞存在明暗两类细胞。     

小鼠眼神经注入Dil后三叉神经节的形态学研究

目的：经眼神经注入DiI研究小鼠三叉神经节的形态学结构。方法：小鼠10只,体重25—30克,雌雄不拘,进行灌注固定后,在外科显微镜下开颅并确认三叉神经节和眼神经,分别于双侧眼神经植入DiI染色晶体。37℃恒温箱放置3个月,待DiI染色晶体扩散后,取出植入DiI染色晶体的眼神经和三叉神经节,再根据神经走向切片,通过荧光显微镜观察DiI染色晶体在三又神经节内的分布。结果：眼神经离三叉神经节约1cm处植入DiI染色晶体后,应用荧光显微镜明视野观察,均可见到高密度标记的眼神经纤维,行向后内,穿经眶上裂入颅。逐步靠近三叉神经节外上方,并进入三叉神经节内,眼神经标记的神经元位于三叉神经节的前内侧。在三叉神经节内可见到DiI标记的神经节细胞及神经纤维。神经纤维平行致密排列,并被神经节细胞神经纤维分隔成群或簇。神经节细胞呈圆形和卵圆形,大小不一,部分节细胞呈蜂窝状排列。亦可见神经元的突起,有的呈螺旋状连于胞体,有的呈线状连于胞体,并可见到双极神经元。结论：小鼠经眼神经注入DiI后,三叉神经节细胞和神经纤维的排列循序跟其他动物基本一致。     

人类胚胎三叉神经节细胞的局在性分布

目的:应用三维重建方法对人类胚胎三叉神经节细胞的局在性分布进行研究。方法:本研究选用非疾病死亡的引产胚胎标本8例,胎龄20-26周,在获取标本1-4小时内,对标本进行灌流固定。其中2例标本在手术显微镜下开颅取出三叉圣经节,石蜡包埋、冰冻切片、HE染色、光学显微镜下观察、照相,用三位重建技术制作三维立体图片。其余6例标本在手术显微镜下开颅、找出三叉神经三大分支眼神经、上颌神经及下颌神经,各选2例分别注入DiI结晶体、在37℃恒温箱内保存3个月,取出标本、明胶包埋、冰冻切片,在荧光显微镜下观察、照相,用三位重建技术制作三维立体图片。结果:(1)眼神经的节细胞分布于神经节的前内侧、下颌神经的节细胞在神经节的后外侧、上颌神经的节细胞位于眼神经和下颌神经节细胞之间。(2)上颌神经和下颌神经节细胞之间存在少量的重叠。结论:三叉神经节细胞在神经节内由前内侧向后外侧分别为眼神经、上颌神经、下颌神经的顺序排列;上颌神经和下颌神经的起始细胞之间存在少量的重叠现象;三维重建图片结果显示人胚胎三叉神经节细胞即眼神经、上颌神经及下颌神经的起始细胞存在明显的局在性分布特征。     

人胚胎三叉神经节细胞发育初步观察

目的:观察人胚胎三叉神经节细胞随胎龄增长变化发育规律.方法:取19-32周人胚胎三叉神经节,光镜观察,细胞计数,图像分析仪测量三叉神经节细胞面积、周长、直径.结果:随着胎龄增长三叉神经节细胞数目无显著性变化,直径随胎龄增长而增大,面积和周长明显增大.结论:人胚胎三叉神经节细胞形态发育在7-8个月(32周)时达成年水平.     

鱼类面神经节的形态,神经节细胞的分布及三叉神经节的关系

目的:观察面神经节的形态结构,神经节细胞的分布以及三叉神经节之间的关系.方法:用罗非鱼,进行10%福尔马林灌注固定,观察面神经节的形态,位置及与三叉神经节之间的位置关系,取面神经节,三叉神经节,根及分支进行连续切片,利用计算机制作三维立体图像,再观察神经节细胞的分布.结果:①面神经节的形态接近圆形.②面神经节位于颅腔内而三又神经节位于眼眶与颅腔之间的骨组织中.③从面神经节发出的周围突通过三叉神经节,与三叉神经的分支伴行.④神经节细胞在神经节内成团分布.结论:罗非鱼面神经节位于颅腔内,在三又神经节的内侧.     

新疆医科大学基础医学院组织胚胎学教研室

目的:观察国人胚胎三叉神经节细胞分化及发育过程。方法:取水囊引产18-36周国人胎儿三叉神经节,HE染色及透射电镜观察。结果:18-20周胎儿三叉神经节神经元排列紧密,胞质少,可见到数量不多的线粒体,且其内几乎看不到嵴,其它细胞器少。25周时,线粒体嵴变长,粗面内质网雏形出现,有纵形小管出现;27周时可观察到成熟的高尔基复合体,32周后,线粒体、粗面内质网等细胞器发育趋于成熟。到33周电镜下可见溶酶体;36周时细胞内各种细胞器结构和功能基本完善。结论:人胚胎三叉神经节细胞发育过程中随胎龄增加,其结构和功能逐步完善,32～36周(8～9月)是细胞的分化发育重要时期。     

鱼类三叉神经节的形态及神经节细胞的分布

目的:观察三叉神经节的形态结构及神经节细胞的分布。方法:用罗非鱼,进行40g/L甲醛灌注固定,观察三叉神经节的位置及分支分布,取三叉神经节,根及分支进行连续切片制作三维立体图像,观察神经节细胞的分布。结果:①三叉神经根在菱脑高度进出脑。②三叉神经节位于眼眶与颅腔之间的骨组织中。③从神经节发出的第一支(眼神经)通过眼眶的背侧分布于吻侧部,第二支(上颌神经)通过眼眶的腹侧分布于上颌部,第三支(下颌神经)通过眼眶的最腹侧分布于下颌部。④神经节细胞在神经节内背腹方向排列的一群细胞团。结论:罗非鱼三叉神经节是独立存在的,与其它鱼类的神经节有明显差异。     

逆行追踪法对鱼类三叉神经节细胞的定位研究

目的:应用逆行追踪法研究罗非鱼三叉神经节细胞体在神经节内的分布特征.方法:罗非鱼浸入140mg/L三卡因间氨苯酸乙脂甲磺酸盐{tricaine methanesulfonate(MS222)}溶液中麻醉,在手术显微镜下暴露神经,通过生物胞素(Biocytin)结晶逆行追踪技术研究定位硬骨鱼类三叉神经节内细胞体的位置.结果:①眼神经、上颌神经、下颌神经的神经节细胞胞体分别位于同侧三又神经节的背侧部、中间部和腹侧部.②上颌神经和下颌神经的细胞在神经节内存在着重叠.结论:罗非鱼三叉神经节细胞在神经节内具有局在性分布.     

人胚胎三叉神经节细胞电镜及光镜观察

目的:观察人胚胎三叉神经节的形态结构.方法:收集非疾病死亡的引产胎儿4例,胎龄6～7个月,常规灌注固定,取三叉神经节进行光镜及电镜观察.结果:①光镜下节细胞呈圆形或椭圆形,胞质内可见大的尼氏颗粒,细胞核近圆形,呈空泡状,核仁基本居中;②电镜下节细胞的胞质内细胞器丰富,可见大量线粒体、发育较好的高尔基复合体、粗面内质网及游离核糖体,核膜凹凸不平,核孔多.结论:胎龄6～7个月人胚胎三叉神经元显示为成熟细胞特征.     

P2X3受体在感觉神经节的表达

用免疫组织化学与原位杂交研究P2X3受体在背根神经节,三叉神经节和结状神经节的分布。结果显示：1、原位杂交;在三种感觉神经节中,95%左右的神经节细胞为P2X3mRNA阳性,中、小型神经节细胞的杂交信号一般要比大型的神经节细胞强一些,2、免疫组织化学;免疫组织化学结果与原位杂交结果基本一致。此外,在各神经节内,均显示出许多P2X3免疫阳性神经纤维,在足掌表皮也显示许多P2X3免疫反应阳性纤维,结果提示：P2X3不仅参与机体的痛觉的形成,还可能参与其它感觉,如本体感觉等的形成。     

The anatomy of two functional types of mechanoreceptive 'free' nerve-ending in the head skin of Xenopus embryos

The structure of the two functional types of 'free' nerve-ending in the head skin of late Xenopus embryos has been examined by horseradish peroxidase staining through their cells in the trigeminal ganglion and by electron microscopy. Type I neurites are identified as the 'movement' detectors by their purely homolateral innervation. They have many fine branches between the superficial skin cells, bearing numerous large varicosities. Type II neurites cross the midline to innervate both sides of the head as do the 'rapid transient' detectors found by physiology. They have a few fairly straight branches between the skin cell layers with few elongated varicosities.     

The chicken trigeminal ganglion. I. An anatomical analysis of the neuron types in the adult

An anatomical analysis of the chicken trigeminal ganglion was made using light microscopy on specimens prepared by usual chemical fixation or freeze-drying methods and by electron microscopy. Two types of neurons were consistently seen, dark and light cells. Dark cells contained a dense cytoplasm with Nissl substance distributed evenly throughout, whereas light cells had a less dense cytoplasm containing clumps of Nissl substance. The Nissl bodies in light cells contained only a few small cisternae of granular endoplasmic reticulum as compared with many stacked cisternae in Nissl bodies of dark cells. The ratio of dark to light cells was approximately 62:38 in all regions of the ganglion. Dark cells were consistently smaller than light cells. In the seven-day old chick, the mean diameters of the dark and light neurons were 21.4 μ and 29.5 μ respectively; in the adult the values were 29.9 μ and 39.7 μ respectively. It is concluded that the dark and light cells belong to two distinct neuronal cell populations.     

Cadherin‐7 mediates proper neural crest cell–placodal neuron interactions during trigeminal ganglion assembly

The cranial trigeminal ganglia play a vital role in the peripheral nervous system through their relay of sensory information from the vertebrate head to the brain. These ganglia are generated from the intermixing and coalescence of two distinct cell populations: cranial neural crest cells and placodal neurons. Trigeminal ganglion assembly requires the formation of cadherin‐based adherens junctions within the neural crest cell and placodal neuron populations; however, the molecular composition of these adherens junctions is still unknown. Herein, we aimed to define the spatio‐temporal expression pattern and function of Cadherin‐7 during early chick trigeminal ganglion formation. Our data reveal that Cadherin‐7 is expressed exclusively in migratory cranial neural crest cells and is absent from trigeminal neurons. Using molecular perturbation experiments, we demonstrate that modulation of Cadherin‐7 in neural crest cells influences trigeminal ganglion assembly, including the organization of neural crest cells and placodal neurons within the ganglionic anlage. Moreover, alterations in Cadherin‐7 levels lead to changes in the morphology of trigeminal neurons. Taken together, these findings provide additional insight into the role of cadherin‐based adhesion in trigeminal ganglion formation, and, more broadly, the molecular mechanisms that orchestrate the cellular interactions essential for cranial gangliogenesis.     

Somatostatin-like immunoreactivity in the retinae of adult and embryonic chickens

Somatostatin, a tetradecapeptide that inhibits growth hormone release, has a widespread distribution in the central and peripheral nervous systems and other cell types. In the present investigation, the chicken neural retina was studied for the presence of structures exhibiting somatostatin-like immunoreactivity by utilizing an indirect immunofluorescence technique. Controls for specificity of staining were performed on alternate sections. Several types of distinctly labeled neurons and their processes were evident in sections of adult and late embryonic retinae. Cresyl violet staining showed that these neurons, which were scattered peripherally and more numerous centrally, occupied several strata within the inner nuclear, inner plexiform, and ganglion cell layers. Labeled neurites of immunoreactive perikarya coursed within these layers as well, often approaching other immunoreactive cells and fibers. The morphology and position of the somatostatin-containing neurons indicated that these neurons were amacrine, horizontal, or ganglion associational cells. These findings indicate that somatostatin is first detectable in the retina during the late embryonic stages of the chicken.     

Neurite regeneration of long-term cultured adult insect neurosecretory cells identified as DUM neurons

A distinctive group of neurons having cell bodies located along the midline of the dorsal surface of the sixth abdominal (A6) ganglion of the adult cockroach Periplaneta americana has been characterized by direct anterogradc cobalt chloride staining. These neurons identified as dorsal unpaired median (DUM) neurons, present a T-shaped morphology. The soma gives rise to a single primary neurite running anteriorly in the ganglion before dividing into two lateral neurites which run into the left and the right side of the ganglion. A characteristic dendritic arborization arises from the lateral neurites within the ganglion. This major branching pattern is mainly located at the periphery of the A6 ganglion and forms a symmetrical complicated network. A new culture procedure of these same adult DUM neurons has been developed from the dissociation of the median parts of the A6 ganglia. In our experimental conditions, we show that cultured adult DUM neurons can survive for several weeks, and regenerate a single primary neuritc dividing into two symmetrical lateral neurites with a number of fine processes radiating from the endings. This corresponds to the typical DUM neuron morphology revealed in situ on the same preparation using the cobalt chloride staining technique. This culture system developed for the first time on A6 ganglia adult DUM neurons will allow a better understanding of the physiological intracellular mechanisms involved in the neurosecretory functions of DUM neurons, which are currently unknown.     

Neurosecretion in the scorpion Heterometrus swammerdami

Gross morphology, staining characteristics and mapping of the diversity of the neurosecretory cell types in the brain and subesophageal ganglion of the scorpion Heterometrus swammerdami are reported. Special neurosecretory cell groups whose product is stainable with orange-G, acid fuchsin and Heidenhain's hematoxylin are present in the brain. In many of the living isolated neurosecretory cells, the secretory material appears luminous when viewed with dark ground illumination and granular when observed with phase contrast microscope. In the subesophageal ganglion the metameric arrangement of neurosecretory cells is distinct. Neurosecretory product accumulating in specific regions of subesophageal ganglion, and its axonal transport into the dorsal nerves and their termination in cephalic blood vessels apparently representing a storage and release organ of neurosecretion is reported.     

Embryonic origin of avian corneal sensory nerves.

Sensory nerves play a vital role in maintaining corneal transparency. They originate in the trigeminal ganglion, which is derived from two embryonic cell populations (cranial neural crest and ectodermal placode). Nonetheless, it is unclear whether corneal nerves arise from neural crest, from placode, or from both. Quail-chick chimeras and species-specific antibodies allowed tracing quail-derived neural crest or placode cells during trigeminal ganglion and corneal development, and after ablation of either neural crest or placode. Neural crest chimeras showed quail nuclei in the proximal part of the trigeminal ganglion, and quail nerves in the pericorneal nerve ring and in the cornea. In sharp contrast, placode chimeras showed quail nuclei in the distal part of the trigeminal ganglion, but no quail nerves in the cornea or in the pericorneal nerve ring. Quail placode-derived nerves were present, however, in the eyelids. Neural crest ablation between stages 8 and 9 resulted in diminished trigeminal ganglia and absence of corneal innervation. Ablation of placode after stage 11 resulted in loss of the ophthalmic branch of the trigeminal ganglion and reduced corneal innervation. Noninnervated corneas still became transparent. These results indicate for the first time that although both neural crest and placode contribute to the trigeminal ganglion, corneal innervation is entirely neural crest-derived. Nonetheless, proper corneal innervation requires presence of both cell types in the embryonic trigeminal ganglion. Also, complete lack of innervation has no discernible effect on development of corneal transparency or cell densities.     

CT引导下立体定向射频热凝三叉神经半月节对原发性三叉神经痛的疗效分析

目的：分析CT引导下立体定向射频热凝三叉神经半月节对原发性三叉神经痛的疗效,探讨其临床适用性。方法：选择从2011年5月至2012年12月于我院住院治疗原发性三叉神经痛的58例患者,在三维CT引导下采用通过BrainLAB手术计划系统经前入路卵圆孔穿刺三叉神经半月神经节,术中根据疼痛分布范围射频热凝三叉神经半月节。观察并比较治疗前后的VAS评分,临床疗效,术中和术后不良反应情况。结果：58例患者的穿刺手术均成功,术后1d、3d、6d的VAS评分均较治疗前显著降低（P〈0．01）;1周后58例患者中,有53例患者疼痛完全消失,l例患者偶然出现疼痛,但无需服用药物处理,共显效54例;4例患者疼痛有所减轻或疼痛发作频率降低,但仍需服用药物,或服用药物剂量较治疗前明显减少;疼痛无改善或者非用药不能缓解的持续痛仅1例。总有效例数为57例,总有效率达98．26％。术中发生不良反应6例,在术后均有所缓解。术后发生各种并发症共15例,均未明显影响手术效果。结论：CT引导可以较为准确的进入穿刺部位,使立体定向射频热凝三叉神经半月节手术更加顺利,达到治疗原发性三叉神经痛的理想效果,适合临床长期推广应用。