Department of Physiology, McGill University, Montreal, Quebec H3G 1Y6, Canada.
Dev Biol. 1981 Jun;84(2):341-50. doi: 10.1016/0012-1606(81)90402-4.
Muscle cells, derived from 1-day-old embryos of Xenopus laevis, were cultured in the absence of nerve and then examined histochemically for cholinesterase activity. Virtually all of the cells exhibited one or more discrete patches of cholinesterase activity on their surface. The patches were located not only on the lower cell surface which was apposed to the floor of the culture dish but also on the lateral and upper surfaces which were not apposed to any solid substrate. At many of the cholinesterase patches the cell surface was invaginated and the invaginations also became filled with the histochemical reaction product. Surface sites of cholinesterase activity were often associated with a thickened plasma membrane and overlying basal lamina-like material. Regions of the cell surface without cholinesterase were typically smooth and ultrastructurally unspecialized. The cholinesterase patches and their associated ultrastructural features developed in the absence of electrical and contractile activity. The similarities between the muscle specializations at cholinesterase sites on cultured, noninnervated, Xenopus muscle cells and those at the neuromuscular and myotendinous junctions of normal skeletal muscle are discussed.
从非洲爪蟾（Xenopus laevis）1 日龄胚胎中分离得到的肌肉细胞，在没有神经的情况下培养，然后通过组织化学方法检查乙酰胆碱酯酶活性。实际上，所有细胞的表面都有一个或多个离散的乙酰胆碱酯酶活性斑。这些斑块不仅位于与培养皿底部相贴的细胞下表面，而且还位于不与任何固体底物相贴的侧面和上表面。在许多乙酰胆碱酯酶斑块处，细胞膜向内凹陷，凹陷处也充满了组织化学反应产物。乙酰胆碱酯酶活性的表面部位常与增厚的质膜和覆盖的基底膜样物质相关联。没有乙酰胆碱酯酶的细胞表面通常是光滑的，超微结构上没有特殊化。在没有电和收缩活动的情况下，乙酰胆碱酯酶斑块及其相关的超微结构特征会发展。讨论了培养的、未神经支配的非洲爪蟾肌肉细胞中乙酰胆碱酯酶部位的肌肉特化与正常骨骼肌的神经肌肉和肌肌腱接头之间的相似之处。
