Ivlev S V, Papidze G P
Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Peterburg.
Gen Physiol Biophys. 1993 Oct;12(5):391-9.
Changes in neuromuscular transmission and ultrastructure of synapses taking place after motor nerve cutting during 20 subsequent days were studied on the wing muscle of the locust (muscle 120) using intracellular recording from phasic fibres. The membrane potential (MP) and the excitatory postsynaptic potential (EPSP) showed practically no changes in comparison with the controls through day 8 after denervation. After the development of a neuromuscular transmission block between days 8 and 14, EPSP and miniature EPSP (MEPSP) disappeared, and the MP level somewhat decreased in comparison with controls. MEPSP frequency and amplitude increased in the first days after denervation. The sensitivity to glutaminic acid (Glu) gradually increased after nerve cutting, reached maximum on day 8 and remained at the same level subsequently (threshold concentration 0.003 mmol/l vs 0.3 mmol/l in the control). At the same time, the maximum amplitude of depolarization produced by Glu increased 1.5-2 times but slightly decreased subsequently. Beginning from day 4 after denervation synaptic vesicles began forming separate groups. On day 14 vesicles were grouped in macroconglomerates at a distance from the presynaptic membrane. On day 20 no axon profiles could be detected. The results suggest a similarity of denervation changes in insect wing and leg muscles.
利用对相位纤维的细胞内记录，在蝗虫翅肌（120 号肌肉）上研究了运动神经切断后 20 天内神经肌肉传递和突触超微结构的变化。与对照组相比，去神经支配后第 8 天，膜电位（MP）和兴奋性突触后电位（EPSP）几乎没有变化。在第 8 天至第 14 天出现神经肌肉传递阻滞之后，EPSP 和微小兴奋性突触后电位（MEPSP）消失，与对照组相比，MP 水平有所下降。去神经支配后的头几天，MEPSP 的频率和幅度增加。神经切断后，对谷氨酸（Glu）的敏感性逐渐增加，在第 8 天达到最大值，随后保持在同一水平（阈值浓度在对照组中为 0.3 mmol/l，在去神经组中为 0.003 mmol/l）。与此同时，Glu 产生去极化的最大幅度增加了 1.5 - 2 倍，但随后略有下降。从去神经支配后第 4 天开始，突触小泡开始形成单独的群体。在第 14 天，小泡在距突触前膜一定距离处聚集成大的团块。在第 20 天，未检测到轴突轮廓。结果表明昆虫翅肌和腿肌的去神经支配变化具有相似性。
