Detachment of structurally intact nerve endings from chromatolytic neurones of rat superior cervical ganglion during the depression of synaptic transmission induced by post‐ganglionic axotomy.
Detachment of structurally intact nerve endings from chromatolytic neurones of rat superior cervical ganglion during the depression of synaptic transmission induced by post‐ganglionic axotomy.
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在节后轴突切断术引起的突触传递抑制过程中，结构完整的神经末梢与大鼠颈上神经节的溶色神经元分离。
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发表时间：
1975
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影响因子：
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通讯作者：
V. Nelson
中科院分区：
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作者：
M. Matthews;V. Nelson
1.电生理学研究表明，节后神经纤维的损伤导致大鼠上级颈神经节突触传递的严重和长期抑制，在24小时内开始。这与以前在其他物种和其他神经元上的研究结果一致。2.神经节后轴突切断术后的电子显微镜检查显示突触前类型的神经末梢具有突触区的所有专门的膜相关特征，但不与任何突触后神经元件并列。这些不寻常的轮廓被解释为分离的突触前神经末梢。在正常和对照神经节中，这些轮廓最多占所有突触前类型含囊泡轮廓的0-5%;在术后3 - 7天，所有主要节后分支切断的神经节中，比例上升至约7%。在此期间，溶色素神经元的平均发生率为74- 6%。3.同时，神经节内突触的发生率下降了约75%，在术后3 - 7天达到最低水平。突触分离后突触后膜特化（“膜增厚”）持续存在的证据少得惊人。4.在较长的生存时间间隔突触的发病率逐渐增加，和分离的神经末梢逐渐减少，恢复良好的42天。5.突触发生率的下降与神经节中桥粒样附着发生率的下降密切相关;发现这种附着的发生率与突触的发生率在很大程度上相关。6.结论：交感神经元上的大部分或全部突触在这些神经元对轴突切断的染色质溶解反应过程中发生物理解离。超微结构特化的突触后位点未能持续存在，桥粒的丢失（特别是那些涉及纯粹的节后神经成分的桥粒）表明节后神经元正在失去其所有的附着特化。7.一些证据表明，卫星细胞可能影响突触前和突触后结构之间的最终分离。
1. Electrophysiological studies showed that injury of post‐ganglionic nerve fibres leads to severe and prolonged depression of synaptic transmission through the rat superior cervical ganglion, beginning within 24 h. This is in line with the results of previous studies in other species and upon other neurones. 2. electron microscopy after post‐ganglionic axotomy revealed nerve endings of presynaptic type with all the specialized membrane‐related features of a synaptic zone, but which were not apposed to any post‐synaptic nervous element. These umusual profiles were interpreted as detached presynaptic nerve endings. In normal and control ganglia, such profiles formed at most 0–5% of all vesicle‐containing profiles of presynaptic type; in ganglia with all major post‐ganglionic branches cut the proportion rose to approximately 7%, between 3 and 7 d post‐operatively. Over this period, the mean incidence of chromatolytic neurones was 74–6%. 3. Concomitantly, the incidence of synapses within the ganglion fell by about 75%, reaching its lowest levels between 3 and 7 d post‐operatively. There was strikingly little evidence of persistence of post‐synaptic membrane specializations (‘membrane thickenings’) following detachment of synapses. 4. At longer survival intervals the incidence of synapses gradually increased, and that of detached nerve endings gradually decreased; recovery was well advanced by 42 d. 5. The fall in the incidence of synapses was closely paralleled by a fall in the incidence of desmosome‐like attachments in the ganglion; the incidence of such attachments was found to be correlated to a significant degree with that of synapses. 6. It is concluded that most or all of the synapses upon sympathetic neurones become physically dissociated during the chromatolytic reaction of these neurones to axotomy. The failure to persist of ultrastructurally specialized post‐synaptic sites, and the loss of desmosomes (particularly marked for those involving purely post‐ganglionic nervous elements) suggest that the post‐ganglionic neurone is losing all its specializations for attachment. 7. Some evidence suggests that the satellite cells may effect the final separation between pre‐ and post‐synaptic structures.