CYTOPLASMIC ARCHITECTURE OF THE AXON TERMINAL - FILAMENTOUS STRANDS SPECIFICALLY ASSOCIATED WITH SYNAPTIC VESICLES
CYTOPLASMIC ARCHITECTURE OF THE AXON TERMINAL - FILAMENTOUS STRANDS SPECIFICALLY ASSOCIATED WITH SYNAPTIC VESICLES
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DOI：
10.1016/0306-4522(91)90143-c
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发表时间：
1991-01-01
期刊：
影响因子：
3.3
通讯作者：
HASHIMOTO, PH
中科院分区：
文献类型：
--
作者：
GOTOW, T;MIYAGUCHI, K;HASHIMOTO, PH
采用速冻深刻蚀法对大鼠中枢神经组织轴突、末梢的细胞质结构进行了研究，以确定突触囊泡及其相关的细胞质环境在末梢的组织结构，并了解这些结构如何参与神经递质释放的机制。轴质可分为两个区域：一端由线粒体占据，称为线粒体区域；另一端位于外围，完全充满直径50-60纳米的球形突触囊泡，称为突触囊泡区域。线粒体结构域最显著的特征是有许多微管通过丝状链与线粒体相连。直径80- 100nm的大囊泡优先与线粒体结构域相关，并与出现的微管相连。突触囊泡结构域的细胞质基质比线粒体结构域的细胞质基质显示出更多的纤维结构，这是因为与突触囊泡相关的丝状链的分布。与连接膜结合细胞器和微管的链（平均8.3纳米厚，23.0纳米长）相比，这些链明显更厚更长（平均11.7纳米厚，42.7纳米长），并将囊泡相互连接或与质膜连接，在囊泡周围形成复杂的网络。此外，两条链在尺寸上与肌动蛋白丝（平均9.9 nm厚，73.5 nm长）有显著差异，表现出5 nm的轴向周期性。这些链，尤其是突触囊泡相关的链，包括它们的网络，很容易被洗涤剂处理或化学固定所破坏，这表明它们本质上是非常脆弱的。颗粒状物质呈球形，大小不一（直径6- 20nm），在突触囊泡区域比在线粒体区域更明显。突触囊泡区域更多的纤维状和颗粒状细胞质结构可能对突触囊泡在释放递质中发挥重要作用至关重要。
Cytoplasmic architecture of axon, terminals in rat central nervous tissue was examined by quick-freeze deep-etch method to determine how synaptic vesicles and their associated cytoplasmic environment are organized in the terminal and to know how these structures participate in the mechanism for neurotransmitter release. The axoplasm is divisible into two domains: one occupied by mitochondria in the middle of the terminal, called the mitochondrial domain, the other situated in the periphery and exclusively filled with spherical synaptic vesicles, 50-60 nm in diameter, the synaptic vesicle domain. The most characteristic feature of the mitochondrial domain was the appearance of many microtubules connected with mitochondria by filamentous strands. Large vesicles, 80-100 nm in diameter, were preferentially associated with the mitochondrial domain, and linked with microtubules wherever they appeared. The cytoplasmic matrix of the synaptic vesicle domain showed a more fibrillar texture than that of the mitochondrial domain because of the distribution of filamentous strands associated with synaptic vesicles. These strands were significantly thicker and longer (mean 11.7 nm thick and 42.7 nm long) than those linking membrane-bound organelles to microtubules (mean 8.3 nm thick and 23.0 nm long), and connected vesicles to one another or to the plasma membrane, making a complicated network around the vesicles. Further, both strands were significantly different in dimension from actin filaments (mean 9.9 nm thick and 73.5 nm long) showing 5-nm axial periodicity. These strands, especially synaptic vesicle-associated ones including their network, were readily broken down in the most part by detergent treatment or chemical fixation, indicating that they are very delicate in nature. Granular materials, which are spherical and vary in size (6-20 nm in diameter), are also more conspicuous in the synaptic vesicle domain than in the mitochondrial domain.More fibrillar and granular cytoplasmic structure of the synaptic vesicle domain may be crucial for synaptic vesicles to perform an essential role in releasing the transmitter.