前庭毛细胞的反相激活模式

分布在内耳前庭各个终器的感觉毛细胞可分为两种类型,它们分别是I型毛细胞和II型毛细胞。这两种毛细胞无论是在静纤毛的长度,还是毛细胞细胞体的形状,或者神经末梢的连接方式以及与之相联系的前庭神经元都不一样。前庭毛细胞感受重力或体位改变刺激的机制是由于其插入到覆盖在其上方耳石膜或终帽内的纤毛随着这些辅助结构的惯性位移而发生弯曲,纤毛的弯曲引起毛细胞膜电位发生去极化或超极化改变,从而促使毛细胞的神经冲动信号发放增强或减弱。静纤毛朝着动纤毛的方向弯曲形成对毛细胞的兴奋性刺激,而静纤毛朝着背离动纤毛的方向弯曲则构成对毛细胞的抑制。球囊斑和椭圆囊斑都被从其中心穿越的一条狭窄的细胞带划分为两个区域,这条狭窄的细胞带被称之为微纹区,在椭圆囊斑微纹区两侧周边区毛细胞的动纤毛都排列在朝向微纹区的位置,而球囊斑微纹区两侧周边区毛细胞的动纤毛都排列在背离微纹区的位置,由此可见,每一个囊斑微纹区两侧毛细胞的极性正好完全相反。当机体沿着一个囊斑的平面从垂直于微纹区的方向产生一个加速运动时,该囊斑一侧周边区的毛细胞会因为静纤毛朝着动纤毛的方向弯曲使该侧毛细胞发生去极化而处于兴奋状态,而另一侧周边区的毛细胞却因静纤毛朝着离开动纤毛的方向弯曲使该侧毛细胞发生超极化而处于抑制状态。三个壶腹嵴上毛细胞的动纤毛都是朝着或背离椭圆囊的统一方向,其中外半规管壶腹嵴上每个毛细胞的动纤毛都是统一朝着椭圆囊,而上半规管和后半规管壶腹嵴上的每个毛细胞的动纤毛都是统一朝着半规管的方向。壶腹嵴是一个位于壶腹腔内的横位的马鞍形隆起,当其上方覆盖的胶状质终帽随着内淋巴液的流动发生相对位置移动时,壶腹嵴一侧的毛细胞纤毛必然会随着终帽顶部的偏移而发生方向一致的弯曲,从而使这半侧壶腹嵴毛细胞产生同步的去极化或超极化反应,然而壶腹嵴另外一侧毛细胞的纤毛却会因为内淋巴液在壶腹嵴上方推动终帽时在被壶腹嵴遮挡一侧的底部形成一个反方向的漩涡式回流使壶腹嵴另外一侧毛细胞的纤毛发生方向相反的弯曲,从而使壶腹嵴两侧毛细胞处于一侧兴奋而另一侧抑制的截然相反的不平衡状态。这意味着同样的加速运动方向对与之相对应的前庭终器两侧感觉上皮产生的是截然不同的刺激信号,从而造成该前庭终器两侧感觉上皮输入信号的不平衡。这种不平衡刺激模式经前庭周边神经元传入到前庭中枢神经系统,使整个从周边到中枢的前庭系统都是以这种不平衡刺激方式传递和感知机体的平衡状态。     

Smad4 条件基因敲除小鼠前庭终器形态学研究

目的研究Smad4条件基因敲除小鼠前庭终器形忿改变，探讨Smad4基因对于前庭发育的作用。方法利用建立的Smad4条件基测敲除小鼠模型．通过光镜观察Smad4（＋／＋）、Smad4（＋／-）与Smad4（-／-）三种基因型小鼠（0．5、1．5月龄）的球囊及囊斑、椭圆囊及囊斑、半规管及壶腹嵴、前庭神经节、内淋巴管与囊的形态结构、毛细胞的形态及排列缺失情况。通过扫描电镜观察球囊斑、椭圆囊斑和壶腹嵴的形态结构、毛细胞及纤毛的排列缺失情况。结果Smad4（-／-）小鼠个体及内耳明显小于Smad4（＋／＋）和Smad4（＋／-），而后面二者区别不大。所有小鼠的球囊及囊斑、椭圆囊及囊斑、半规管、前庭神经节、内淋巴管与囊的大小和结构正常，淋巴囊腔饱满，囊斑处的感觉上皮、耳石、毛细胞及纤毛排列整齐，没有发现明显的病变．三个基因型间没有差异。Smad4（-／-）小鼠壶腹嵴囊性变多且严重、后半规管壶腹嵴出现明显的副嵴、偶尔可见壶腹嵴感觉上皮空泡样变。壶腹嵴的毛细胞和支持细胞排列整齐，形态无明显改变，未见缺失。扫描电镜示球囊斑、椭圆囊斑、后、外、上半规管壶腹嵴正常，三个基因型之间没有差异。结论Smad4（-／-）小鼠的前庭终器有轻微病理改变，Smad4（＋／＋）与Smad4（＋／-）小鼠的前庭终器形态结构基本正常．表明Smad4对于前庭终器的发育影响可能不明显。     

人前庭感觉上皮扫描电镜观察

为了解人前庭器官的超微结构，借助扫描电镜技术观察了５人（１０耳）的前庭感觉上皮。结果显示：①球囊斑呈“Ｌ”形，椭圆囊斑形如打开的贝壳；②Ⅰ型感觉细胞呈烧瓶样，Ⅱ型感觉细胞呈试管状；③感觉细胞纤毛排列呈阶梯状，动纤毛最长，且位于最长的静纤毛一侧，椭圆囊斑最长的静纤毛和动纤毛靠近微纹，其极性也向微纹，球囊斑则背离微纹，水平半规管壶腹嵴的动纤毛朝向椭圆囊侧，上、后半规管壶腹嵴则朝向半规管侧；④耳石形状大小不一致，呈现两端为锥形的圆柱状晶体。     

前庭学

970618哺乳动物前庭迷路的体外发育:周围性眩晕的研究手段/周祥宁…//天津医药一1 996,24(l)一4一7 首次在国内报告小鼠前庭迷路的体外发育。采用周祥宁和Van De Water建立的HEMA水凝胶器官培养法培养第12一13天CBA/C57小鼠胚胎的内耳原基7一8天。内耳原基的上部发育成3个半规管、椭圆囊和球囊。半规管的壶腹晴由一排感觉毛细胞和2一3排支持细胞构成。晴的上方有正在发育的峪顶。椭圆囊斑和球囊斑的表面都有一层耳石膜。这些囊斑内可见一层感觉毛细胞和1一2层支持细胞。超微结构研究发现壶腹峪、椭圆囊斑和球囊斑的毛细胞有排列规则的…     

人前庭感觉上皮扫描电镜观察

为了解人前庭器官的超微结构，借助扫描电镜技术观察了５人（１０耳）的前庭感觉上皮。结果显示：①球囊斑呈“Ｌ”形，椭圆囊斑形如打开的贝壳；②Ｉ型感觉细胞呈烧瓶样，Ⅱ型感觉细胞呈试管状；③感觉细胞纤毛排列呈阶梯状，动纤毛最长，且位于最长的静纤毛一侧，椭圆囊斑最长的静纤毛和动纤毛造近微纹，其极性也向微纹，球囊斑则背离微纹，水平半规管壶腹嵴的动纤毛朝向椭圆囊侧，上、后半规管过来腹嵴则朝向半规管侧；④耳右形状     

前庭学

990986人前庭感觉上皮扫描电镜观察/孙建和…//中华耳鼻咽喉科杂志一1998,33(增刊)(英文版)一31一33 目的:了解人前庭器官的超微结构。方法:借助扫描电镜技术观察了5人(10耳)的前庭感觉上皮。结果:①球囊斑呈“L”形,椭圆囊斑形如打开的贝壳;②I形感觉细胞呈烧瓶样,l形感觉细胞呈试管状;③感觉细胞纤毛排列呈阶梯状,动纤毛最长,且位于最长的静纤毛一侧,椭圆囊斑最长的静纤毛和动纤毛靠近微纹,其极性也向微纹,球囊斑则背离微纹,水平半规管壶腹峙的动纤毛朝向椭圆囊侧,上、后半规管壶腹峙则朝向半规管侧;①耳石形状大小不一致,呈现两端为锥形…     

小鼠前庭器官的形态发生

目的了解小鼠前庭器官发育的形态学特征及演变规律.方法利用光镜、扫描电镜、透射电镜观察C57BL/6小鼠从胚胎第8天到刚出生期间前庭器官发育过程中的形态变化.结果 C57BL/6小鼠的前庭器官在胚胎第10.5天开始发育,胚胎第11.5天形成上、后半规管始基,到胚胎第12天水平半规管始基才逐渐形成,椭圆囊已出现许多原始的感觉纤毛,而到胚胎第13天,球囊才开始发育;到胚胎第15天,椭圆囊、球囊、壶腹嵴初具成熟形态,毛细胞和支持细胞也初具雏形,到出生时,前庭器官已基本发育成熟.结论 C57BL/6小鼠前庭感觉细胞在胚胎第12天开始分化,感觉上皮的形态从胚胎第12天至第18天变化最明显.椭圆囊、壶腹嵴的发生较早,随后才形成球囊,到出生时前庭感觉器官已基本发育成熟.     

老年前庭器的退行性变

本文综述了老年前庭器的退行性变文献资料。首先介绍正常的前庭器结构,之后从毛细胞、纤毛、耳石及前庭神经四个方面分别阐述它们的数量及超微结构上的退行性变。最后提出前庭器随年龄增加而出现退行性变,壶腹嵴部明显,Ⅰ型毛细胞较Ⅱ型毛细胞明显。     

前庭学

921369 前庭放射损伤扫描电镜观察的实验研究/范静平…∥上海医学。-1992,15(2)。-96～97 采用扫描电镜观察放射对前庭的影响,发现豚鼠听泡区40GYγ射线照射后,前庭耳石变形,囊斑和壶腹嵴毛细胞纤毛紊乱、倒伏、融化及脱落,少许毛细胞坏死。其病理改变类似耳毒性药物和噪声对前庭的损害。图2参3(原提要)     

前庭毛细胞分离法探讨

取豚鼠球囊、椭圆囊及壶腹嵴，置于含胶原酶的Ｈａｎｋ＇ｓ液中消化，再辅以机械分离方法获得单个离体Ｉ型和Ⅱ型前庭毛细胞。Ｉ型细胞为烧瓶状，有明显颈部、皮板及纤毛。Ⅱ型细胞较Ｉ型细胞为短，无显著颈部，但有皮板及纤毛。Ｉ型细胞与Ⅱ细胞数量之比为１２：１。离体５小时后仍有３５％的前庭毛细胞具有活性。观察结果表明，应用胶原酶能获得较多的具有活性的单个离体前庭毛细胞，为前庭毛细胞，为前庭的重、病理及药理实验研究     

Cholinesterase activity in vestibular organs of young and old mice.

The activities of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) were studied by histochemical methods in the semicircular canal end organs, the utricle and the saccule of young and old mice. AChE was located on the plasma membrane of efferent nerve terminals beneath vestibular hair cells, and along the basement membrane. In the ampulla, stained efferent terminals were more prevalent on the slopes of the crista than in the central region. In all organs examined, there were no discernible differences in AChE activity between young and old mice. BChE activity was observed in the epithelial light cells and supporting cells of the saccule, utricle, and ampulla. Its distribution was similar in both young and old mice in the ampulla, but decreased significantly with age in the utricle. Preliminary data suggest that BChE activity is also weak in old saccular supporting cells. Unlike the utricle, old saccular light cells retained intense BChE activity.     

光学相差显微镜下前庭囊斑两型毛细胞的形态学鉴别

目的:探讨电生理实验中,光学相差显微镜下较为可靠的前庭两型毛细胞辨别标准.方法:对于豚鼠椭圆囊和球囊分离所得的前庭毛细胞,分别对细胞胞体的长、宽以及表皮板纤毛的长度进行测量,并对长宽比和纤毛胞长比进行分析.结果:豚鼠椭圆囊和球囊的两型前庭毛细胞相比,细胞的宽度和纤毛的长度比较差异无统计学意义,Ⅰ型毛细胞的长度明显较长,长宽比较大,纤毛胞长比较小.结论:在既往以是否有明显的颈部来区分两型前庭毛细胞的基础上,结合细胞的长宽比和纤毛胞长比进一步进行辨别,有助于更准确地区分两型毛细胞.     

The crystalline pattern of calcium in different topographical regions of the otoconial membrane. An electron probe and spectroscopic diffraction study.

Quantitative electron probe microanalysis and electron spectroscopic diffraction analysis was used to determine the gradient of distribution of calcium and its crystalline pattern at different levels (lower gelatinous membrane, upper gelatinous membrane and otoliths) in the otoconial membrane of adult OF1 mice. Our quantitative electron probe microanalytical data, obtained with scanning-transmission electron microscopy, indicated that there was a gradient in calcium concentration which increased from the vestibular surface towards the otoliths. Differences between the three regions of the otoconial membrane were statistically significant in both the utricle and saccule. Our results with electron spectroscopic diffraction revealed an increasing crystalline development from the lower gelatinous membrane towards the otoliths. Our findings with both techniques suggest that the gelatinous membrane is involved in the maturation and crystallization of the otoliths.     

Association of the 5-HT2A receptor gene polymorphisms with obstructive sleep apnea hypopnea syndrome in Chinese Han population

Quantitative electron probe microanalysis and electron spectroscopic diffraction analysis was used to determine the gradient of distribution of calcium and its crystalline pattern at different levels (lower gelatinous membrane, upper gelatinous membrane and otoliths) in the otoconial membrane of adult OF1 mice. Our quantitative electron probe microanalytical data, obtained with scanning-transmission electron microscopy, indicated that there was a gradient in calcium concentration which increased from the vestibular surface towards the otoliths. Differences between the three regions of the otoconial membrane were statistically significant in both the utricle and saccule. Our results with electron spectroscopic diffraction revealed an increasing crystalline development from the lower gelatinous membrane towards the otoliths. Our findings with both techniques suggest that the gelatinous membrane is involved in the maturation and crystallization of the otoliths.     

Morphometric analysis and fine structure of the vestibular epithelium of aged C57BL/6NNia mice

The vestibular organs of young and very old C57BL/6NNia (B6) mice were compared by light and electron microscopy. Hair cell density decreased an average of 14% in the utricle, 19% in the saccule and posterior crista, 23% in the horizontal crista, and 24% in the anterior crista. Hair cell size remained the same throughout the mouse's life span as did the ratio of Type I to Type II hair cells. The most apparent sign of advanced age was dense inclusions found in sensory and supporting cells. Although small inclusions were present at five weeks, by 29 months, additional, larger forms appeared. An unusual melanin-like form was characteristic of old Type I hair cells. Synaptic morphology and synaptic bodies were well preserved even in very old B6 mice. Elongated bars were common in Type I hair cells and spheroid synaptic bodies were the most common form in Type II hair cells. Large clusters of synaptic bodies occurring in both young and old mice were seen only in Type I hair cells. Although the B6 strain suffers from genetically determined early cochlear degeneration, it does not experience early degeneration of the peripheral vestibular organs.     

梅尼埃病前庭功能分级的探讨

目的 建立一种新的梅尼埃病患者前庭功能分级方法,初步探索其临床意义及与梅尼埃病听力分期的相关性。 方法 收集112例单侧梅尼埃病患者资料,所有患者均完成包括纯音测听、cVEMP、oVEMP、vHIT以及冷热试验检查。冷热试验和vHIT的结果中任一项异常均视为半规管功能异常。cVEMP结果异常视为球囊功能异常,oVEMP结果异常视为椭圆囊功能异常。球囊、椭圆囊、半规管功能均正常的患者为前庭功能I级,球囊、椭圆囊、半规管功能其中1项异常者为前庭功能Ⅱ级,2项异常者为前庭功能Ⅲ级,3项均异常者为前庭功能Ⅳ级。 结果 根据听力分期,符合入组标准的95例梅尼埃病患者中Ⅰ期13例、Ⅱ期13例、Ⅲ期52例、Ⅳ期17例。患耳平均听阈为(51.86±21.70)dB HL。前庭功能检测结果cVEMP异常率63.2%,oVEMP24异常率74.7%,vHIT异常率33.7%,冷热试验异常率52.6%。前庭功能分级Ⅰ级9例、Ⅱ级28例、Ⅲ级39例、Ⅳ级19例。前庭功能分级与患者的听力差异有统计学意义(P<0.01, r=0.35)。前庭功能分级与患者梅尼埃病分期差异有统计学意义(P<0.01, r=0.35)。前庭功能分级与患者的病程差异有统计学意义(P=0.02, r=0.24)。前庭功能分级与患者的年龄差异无统计学意义(P=0.084)。 结论 梅尼埃病患者随着病程的进展,耳石器功能和半规管功能检测异常率会逐渐增加。通过对球囊、椭圆囊、半规管低频和高频功能的精细化检测,能够对梅尼埃病患者前庭功能进行精准评估。听力分期与前庭功能分级的同步评估能够反映患者疾病的进展状态,同时能够对患者治疗方案的选择和术后康复的预判起到参考作用。     

Vestibular morphology in the mutant mix-mouse

Mix-mice, a new strain of mice with inner ear dysfunction, and their littermates were used in the present study in order to investigate vestibular morphology, visualised by light microscopy (LM) and transmission electron microscopy (TEM). Contrary to the mix-mice, their littermates showed less stained nerve chalices and it was possible to detect that hair cells showed surface herniations and so-called 'blebs' in the apical portion of the epithelium. Sensory hairs showed a disarrayed pattern. The mix-mice had severe microscopical abnormalities: collapse of the membranous cell layer, cavities inside the neuroepithelium, severe loss of hair cells, herniations of the few remaining hair cells and increased supporting cells were evident. In the utricle and saccule, hair cells were missing and the epithelial surface was covered by a single layer of smooth, flattened epithelial cells of hitherto unknown origin.     

Morphometric analysis of the vestibular sensory epithelia of young adult rat

The appearance of vestibular sensory cells and their progressive development has been the subject of many ontogenetic studies. Because deteriorating hair cells are supposed to play a role in balance disorders of the elderly, the final stage of development (i.e. senescence) has been investigated as well. It is generally assumed that the number of hair cells in crista ampullaris, saccule and utricle slowly but steadily decreases with age. However, actual data covering the period between maturation and senescence are scarce. In the present study, rat vestibular epithelia were labeled for actin and tubulin. Morphology was inspected from immediately after weaning until the age of 12 months. Although, postnatal development was no part of this study some data on one day old epithelia are presented for comparison. At postnatal day 1, hair bundles are still shorter than in mature sensory organs, the width of the zonula adherens is less, and the apical cross-sectional area of the epithelial cells is smaller. After one month, maturation is complete. Total cell density is 400-500 per 0.01 mm2, both in the otolith maculae and in the cristae ampullares. During the first year after maturation, no changes in epithelial morphology were observed and cell density remains constant.     

Development and evolution of the vestibular sensory apparatus of the mammalian ear

Herein, we will review molecular aspects of vestibular ear development and present them in the context of evolutionary changes and hair cell regeneration. Several genes guide the development of anterior and posterior canals. Although some of these genes are also important for horizontal canal development, this canal strongly depends on a single gene, Otx1. Otx1 also governs the segregation of saccule and utricle. Several genes are essential for otoconia and cupula formation, but protein interactions necessary to form and maintain otoconia or a cupula are not yet understood. Nerve fiber guidance to specific vestibular end-organs is predominantly mediated by diffusible neurotrophic factors that work even in the absence of differentiated hair cells. Neurotrophins, in particular Bdnf, are the most crucial attractive factor released by hair cells. If Bdnf is misexpressed, fibers can be redirected away from hair cells. Hair cell differentiation is mediated by Atoh1. However, Atoh1 may not initiate hair cell precursor formation. Resolving the role of Atoh1 in postmitotic hair cell precursors is crucial for future attempts in hair cell regeneration. Additional analyses are needed before gene therapy can help regenerate hair cells, restore otoconia, and reconnect sensory epithelia to the brain.