ACETYLCHOLINESTERASE ACTIVITY IN THE MYOTUBE AND MUSCLE SATELLITE CELL OF THE FETAL RABBIT AN ELECTRON MICROSCOPIC-CYTOCHEMICAL AND BIOCHEMICAL STUDY
ACETYLCHOLINESTERASE ACTIVITY IN THE MYOTUBE AND MUSCLE SATELLITE CELL OF THE FETAL RABBIT AN ELECTRON MICROSCOPIC-CYTOCHEMICAL AND BIOCHEMICAL STUDY
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胎兔肌管和肌肉卫星细胞中乙酰胆碱酯酶活性的电子显微镜细胞化学和生物化学研究
DOI：
10.1177/21.7.634
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发表时间：
1973
影响因子：
3.2
通讯作者：
M. Brzin
中科院分区：
文献类型：
--
作者：
V. Tennyson;L. Kremzner;M. Brzin
本文研究了兔胎儿肌管和节外骨骼肌中乙酰胆碱酯酶(AChE)的活性。对正在开发的电机端板进行了一些观察。不溶性和可溶性AChE在所有阶段都存在，但丁酰胆碱酯酶似乎不存在。肌管形成过程中酶活性较高。不溶性AChE可能对应于细胞化学终产物，它与肌管中的网状成分，即核膜、肌浆网和高尔基复合体的某些成分相结合。讨论了含酶网状结构参与早期肌管自发收缩的可能性。随着肌管成熟为早期肌肉，网状结合酶的活性部位显著减少。可溶性AChE可能来源于伴随脊神经至运动终板的含AChE的单个核细胞和雪旺细胞。这些细胞具有随机分布的最终产物，很可能是在这些细胞表面和相邻肌管的肌膜上发现的类似最终产物的来源。讨论了以下可能性：(A)可溶性AChE可能在肌管融合中发挥作用，(B)参与广泛的肌膜乙酰胆碱敏感性，(C)参与连接酶。在含有乙酰胆碱酯酶的单个核细胞中随机分布的最终产物允许追踪其进一步分化。这种细胞看起来像是一种干细胞，可以直接与肌管融合；它可以产生更分化的成肌细胞，以及肌肉卫星细胞。含有乙酰胆碱酯酶的单个核细胞也可能与神经肌肉连接相关的细胞有关。肌肉卫星细胞中的可溶性AChE似乎与该细胞的“活跃”阶段有关，因为酶活性在成体阶段是看不到的，而成体阶段被认为是休眠的。
Acetylcholinesterase (AChE) activity has been studied in the myotube and in extrajunctional skeletal muscle of the rabbit fetus. Some observations on the developing motor end plate are included. Both insoluble and soluble AChE's are present at all stages, but butyrylcholinesterase seems to be absent. Enzymic activity is high during myotube formation. The insoluble AChE probably corresponds to the cytochemical end product which is bound to the elements of the reticulum in the myotube, i.e., the nuclear envelope, the sarcoplasmic reticulum and some elements of the Golgi complex. The possibility that the enzyme-containing reticulum is involved in the spontaneous contraction of early myotubes is discussed. The number of active sites of reticulum-bound enzyme decreases markedly as the myotubes mature into early muscle. The soluble AChE is probably derived from the AChE-containing mononuclear cell and the Schwann cell which accompanies the spinal nerve to the motor end plate. These cells have a random distribution of end product and are probably the source of a similar end product found at the surfaces of these cells and at the sarcolemma of adjacent myotubes. The following possibilities that are discussed are that soluble AChE may (a) play a role in fusion of myotubes, (b) be involved in widespread sarcolemmal acetylcholine sensitivity and (c) contribute to the junctional enzyme. The randomly distributed end product in the AChE-containing mononuclear cell permits the tracing of its further differentiation. This cell appears to be a stem cell, which can fuse directly with the myotube; it can give rise to a more differentiated type of myoblast, as well as to the muscle satellite cell. AChE-containing mononuclear cells may also contribute to the cells associated with the neuromuscular junction. The soluble AChE in the muscle satellite cell seems to be associated with an "active" phase of this cell, since enzymic activity is not seen in the adult stage in which it is presumed to be dormant.