NODAL AND TERMINAL SPROUTING FROM MOTOR NERVES IN FAST AND SLOW MUSCLES OF THE MOUSE
NODAL AND TERMINAL SPROUTING FROM MOTOR NERVES IN FAST AND SLOW MUSCLES OF THE MOUSE
复制标题
DOI：
10.1113/jphysiol.1980.sp013410
复制
发表时间：
1980-01-01
影响因子：
5.5
通讯作者：
IRONTON, R
中科院分区：
文献类型：
--
作者：
BROWN, MC;HOLLAND, RL;IRONTON, R
本文用碘化锌和四氧化锇染色法研究了小鼠后肢快肌和慢肌的结芽和终末芽。通常由肉毒杆菌毒素注射引起的末端发芽可以通过定期和频繁地直接电刺激肌肉纤维来预防。但在部分失神经脊髓标本中，直接肌肉刺激并没有减少由结芽支配的终板数量。在给予不同剂量肉毒杆菌毒素的腿部肌肉中，末端发芽的量与瘫痪的程度线性相关。在部分失神经支配的肌肉，无论是终端发芽的数量，也没有节点发芽的数量与失神经支配的程度。部分失神经支配导致腓骨第三肌和趾长伸肌的快肌比慢比目鱼肌中的节点发芽相对更多，慢比目鱼肌本身比其他肌肉具有更多的终末发芽。只有在肉毒杆菌毒素完全麻痹的情况下，快速肌才能像比目鱼肌一样长出末端芽。没有证据表明脊髓内产生或传播了发芽信号。为了证实早期的工作（Duchen和Strich，Brown和铁顿），终末发芽信号的来源是去神经或以其他方式失活的肌纤维，其作用因变性神经组织的存在而增强。快肌在部分失神经支配时的末端发芽可能比慢肌少，因为快肌经历与不活动相关的变化需要更长的时间，并且因为它们对神经变性的影响具有更高的抵抗力。淋巴结发芽的信号似乎不是来自肌肉纤维，但需要进一步的实验来确定这一点。
A study of nodal and terminal sprouting in fast and slow muscles of the mouse hind limb was made using the zinc iodide and osmium tetroxide stain. The terminal sprouting normally elicited by botulinum toxin injection can be prevented by regular and frequent direct electrical stimulation of the muscle fibers. But the number of endplates innervated by nodal sprouts in partly denervated spinal preparations was not reduced by direct muscle stimulation. In leg muscles given varying doses of botulinum toxin the amount of terminal sprouting was linearly related to the degree of paralysis. In partly denervated muscles neither the amount of terminal sprouting nor the amount of nodal sprouting was correlated with the degree of denervation. Partial denervation causes relatively more nodal sprouting in the fast muscles peroneus tertius and extensor digitorum longus than in the slower soleus muscle, which itself has considerably more terminal sprouting than the others. The fast muscles can develop as much terminal sprouting as the soleus only in response to full paralysis with botulinum toxin. No evidence could be found for a sprouting signal generated or spreading within the spinal cord. In confirmation of earlier work (Duchen and Strich, Brown and Ironton), the source of the signal for terminal sprouting is denervated or otherwise inactivated muscle fibers, whose action is boosted by the presence of degenerating nervous tissue. Fast muscles probably have less terminal sprouting when partly denervated than slow muscles because of the longer time it takes a fast muscle to undergo the changes associated with inactivity and because of their higher resistance to the effects of nerve degeneration. It does not seem that the signal for nodal sprouting comes from the muscle fibers but further experimentation is needed to establish this firmly.