Fine structure observations of denervation and reinnervation of neuromuscular junctions in mouse foot muscle.
Fine structure observations of denervation and reinnervation of neuromuscular junctions in mouse foot muscle.
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小鼠足部肌肉神经肌肉接头去神经支配和神经再支配的精细结构观察。
DOI：
10.2106/00004623-196951060-00012
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发表时间：
1969
期刊：
影响因子：
--
通讯作者：
S. Zacks
中科院分区：
文献类型：
--
作者：
A. Saito;S. Zacks
本文研究了小鼠足肌在神经切断后30周的神经肌肉接头去神经和再神经支配过程中的细微结构变化。
神经切断后第一周末轴突消失，施万细胞和神经周上皮细胞回缩。初级突触间隙变浅，次级突触间隙变短变宽，但充满神经下器的基底层不变。在初级突触间隙的肌肉表面膜的特征性增厚持续存在，并有聚集的核糖体的数量增加。在底板肌浆中观察到包被囊泡的损失。
最早返回的轴突芽在第三周时首次观察到，并在四周时变得众多。这些细胞最初含有很少的、大小不一的突触囊泡，但没有被膜囊泡。在接下来的几周里，初级裂加深，次级裂变长变窄，到15 ~ 30周时，所有研究的神经肌肉接头都具有正常的精细结构。
电子显微镜检查未发现神经肌肉接头从头形成的精细结构证据，但在光学显微镜下研究的双染色切片中观察到偶尔由逃逸纤维形成的小神经肌肉接头。
持久性的神经肌肉接头附近的雪旺氏和神经周上皮细胞的纤细的过程中发挥了重要作用，在指导返回轴突的老网站的神经支配。
The fine structure changes which occurred during denervation and reinnervation of neuromuscular junctions for a period of thirty weeks after nerve section were studied in muscles of the mouse foot.
Axons were absent by the end of the first week after nerve section and there was retraction of Schwann cells and perineural epithelial cells. The primary synaptic cleft became shallow, the secondary clefts, shorter and wider, but the basement lamina filling the subneural apparatus was unaltered. The characteristic thickening of the muscle surface membrane in the primary synaptic cleft persisted, and there were increased numbers of clustered ribosomes. A loss of coated vesicles was observed in the sole-plate sarcoplasm.
The earliest returning axon sprouts were first observed at three weeks and became numerous by four weeks. These originally contained few and variably sized synaptic vesicles but no coated vesicles. In the succeeding weeks the primary clefts deepened, the secondary clefts became elongated and narrower, and, by fifteen to thirty weeks, all neuromuscular junctions studied had normal fine structure.
No fine-structure evidence of de novo formation of neuromuscular junctions was obtained by electron microscopy, although occasional small neuromuscular junctions formed by escaped fibers were observed in dual-stained sections studied in the light microscope.
Persistence of tenuous processes of both Schwann and perineural epithelial cells in the immediate vicinity of denervated neuromuscular junctions appeared to play a major role in guiding returning axons to old sites of innervation.