Three-dimensional structure of the synaptic contact of the neuromuscular junction in the rat lumbrical muscle
Three-dimensional structure of the synaptic contact of the neuromuscular junction in the rat lumbrical muscle
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DOI：
10.1679/aohc.62.237
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发表时间：
1999-08-01
影响因子：
--
通讯作者：
Inoué, T
中科院分区：
文献类型：
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作者：
Sohn, A;Kaidoh, T;Inoué, T
本研究用三种不同的扫描电镜方法：醛前缀-锇-二甲基亚砜-锇法（A-O-D-O法）、细胞抽提法和NaOH消化法，观察了大鼠蚓状肌突触接触的三维结构。这三种方法分别显示了运动神经末梢、神经下基膜和突触后肌膜。运动神经末梢由一簇球形和圆柱形终末组成。突触前膜上的孔被认为是胞吐囊泡的开口。突触后侧的神经下基底层显示出许多脊，对应于交界处的褶皱。大多数山脊从底部垂直升起。脊状突起有变宽、变窄和分支的现象，神经下基片由小颗粒物质组成。初级突触裂的基底层有直径25-30 nm的小孔，这可能有助于乙酰胆碱（ACh）的运输，而不被层内的ACh酯酶水解。在突触后肌膜的外表面，初级突触裂由凹陷和沟槽的混合物组成，这是目前已知的唯一一例。这些凹陷和沟槽似乎分别进入运动神经末梢的球形和圆柱形末端。连接褶的开口由初级突触裂隙中的许多狭缝和一些凹坑组成。
This study examined the three-dimensional structures of the synaptic contact in rat lumbrical muscles by scanning electron microscopy using three different methods: the aldehyde prefix-osmium-dimethyl sulfoxide-osmium method (A-O-D-O method), the cell-extraction method, and the NaOH-digestion method. These three methods visualized the motor nerve endings, subneural basal lamina and postsynaptic sarcolemma, respectively, The motor nerve endings were composed of a cluster of spherical and cylindrical terminals. Pores on the presynaptic membrane were considered openings of exocytotic vesicles. The postsynaptic side of the subneural basal lamina showed numerous ridges, corresponding to junctional folds. Most of the ridges rose vertically from their base. The ridges showed widening, narrowing, and branching, The subneural basal lamina appeared to be composed of small granular substances. The basal lamina of the primary synaptic clefts had pores 25-30 nm in diameter, which may facilitate the transport of acetylcholine (ACh) without being hydrolyzed by ACh esterase in the lamina, On the outer surface of the postsynaptic sarcolemma in a sole plate, the primary synaptic clefts were composed of a mixture of depressions and gutters; so far as we know, this represents the only example of such a phenomenon. These depressions and gutters seem to at respectively into the spherical and cylindrical terminals of the motor nerve endings. The openings of the junctional folds consisted of a mixture of many slits and a few pits in the primary synaptic clefts.