Tipnis U R, Malhotra S K
J Supramol Struct. 1979;12(3):321-34. doi: 10.1002/jss.400120305.
The nonsynaptic sarcolemma of denervated skeletal muscle of rat shows an abundance of approximately 15 nm intramembranous particles on the P face. These particles are either singly distributed or are in clusters, and they are essentialy lacking from the comparable freeze-fractures of the innervated sarcolemma. Autoradiographic studies using 125I-alpha-bungarotoxin (BGT) on 1 mu-thick sections, and freeze-etch studies using ferritin-alpha-BGT conjugates on membrane fractions, show that the distribution of the label corresponds to the distribution of the 15-nm particles in the nonsynaptic sarcolemma. On the basis of these results and existing physiologic and biochemical data, it is suggested that the 15-nm intramembranous particles are components of the alpha-BGT binding sites, ie, acetylcholine (Ach) receptors, in the nonsynaptic sarcolemma of denervated muscle and that the two types of distributions represent two spatial manifestations of Ach receptor molecules. The significance of these findings in relation to synapse formation in denervated muscle is discussed.
大鼠失神经骨骼肌的非突触肌膜在P面显示出大量约15纳米的膜内颗粒。这些颗粒要么单个分布，要么成簇分布，而在受神经支配的肌膜的类似冷冻断裂面上基本没有这些颗粒。使用125I-α-银环蛇毒素（BGT）对1微米厚切片进行的放射自显影研究，以及使用铁蛋白-α-BGT缀合物对膜组分进行的冷冻蚀刻研究表明，标记物的分布与非突触肌膜中15纳米颗粒的分布相对应。基于这些结果以及现有的生理和生化数据，有人提出15纳米的膜内颗粒是失神经肌肉非突触肌膜中α-BGT结合位点（即乙酰胆碱（Ach）受体）的组成部分，并且这两种分布类型代表了Ach受体分子的两种空间表现形式。讨论了这些发现与失神经肌肉中突触形成的关系。
