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联合培养分离的小鼠胚胎脊髓与肌肉小块时,能够形成神经肌肉接头。培养第7天时,肌管被小球状的神经末梢支配,神经与肌管的接触处,未显胆碱酯酶活性;第14天时,神经纤维发出侧支,神经末梢除球状外还有简单的树枝状者。该期内,终板胆碱酯酶活性开始检出。肌纤维呈现多处神经接触,或者数根轴突支配于同一处,形成“混合接触”。胆碱酯酶活性只能检出多个接触中的一个,“混合接触”未能显示酶的活性;第21天时,终板数目和胆碱酯酶活性均显著增加;第30天后,终板的形态结构和酶活性强度与在体幼年小鼠的终板相似。这些终板都为单神经支配。当脊髓和肌肉联合培养时,肌纤维的分化,依赖于运动神经的支配;另一方面,神经元的生长和存活,与肌肉纤维的存在也密切相关。
The co-culture of isolated mouse embryonic spinal cord and muscle fragments can form neuromuscular junctions. On the 7th day of culture, the myotubes were dominated by the small globular nerve endings, the contact between the nerve and the myotubes did not show any cholinesterase activity. On the 14th day, the nerve fibers emitted collateral branches, and the nerve endings were simple in addition to the globular shape Dendrites. During this period, end plate cholinesterase activity began to be detected. Muscle fibers show multiple nerve contacts, or several axons dominating in the same place, forming a “mixed contact.” Cholinesterase activity detected only one of the multiple contacts, “mixed exposure” failed to show enzyme activity; the number of end-plates and cholinesterase activity increased significantly on day 21; after day 30, the endplate The morphological structure and enzymatic activity are similar to those in end-stage juvenile mice. These endplates are all single nerve innervations. When the spinal cord and muscle are co-cultured, the differentiation of muscle fibers depends on the control of motor nerves; on the other hand, the growth and survival of neurons are closely related to the presence of muscle fibers.