Hennig R, Dietrichs E
Department of Neurophysiology, University of Oslo, Norway.
Exp Neurol. 1994 Dec;130(2):331-6. doi: 10.1006/exnr.1994.1211.
When reinnervation is allowed after a sciatic nerve cut in the adult rat, motoneuron axons may branch to innervate antagonistic muscles. This multiple innervation is widespread, but transient. Fourteen weeks after denervation isometric muscle contraction experiments and studies with anterograde transport of the fluorescent tracer Fast Blue showed that branches from the same motoneurons reached the distal part of the tibial nerve and either the soleus or the extensor digitorum longus muscles or both muscles. Retrogradely double-labeled motoneurons were found after injections of different fluorescent tracers into these muscles. Sixty-four to 88 weeks after the nerve cut, similar experiments showed that selective innervation was reestablished. The findings suggest a selective mechanism for axon withdrawal in an adult mammal.
成年大鼠坐骨神经切断后若允许重新神经支配，运动神经元轴突可能会分支去支配拮抗肌。这种多重神经支配很普遍，但却是短暂的。去神经支配14周后，等长肌肉收缩实验以及利用荧光示踪剂快蓝进行顺行运输的研究表明，来自同一运动神经元的分支到达了胫神经远端以及比目鱼肌或趾长伸肌或这两块肌肉。向这些肌肉注射不同荧光示踪剂后发现了逆行双重标记的运动神经元。神经切断64至88周后，类似实验表明重新建立了选择性神经支配。这些发现提示了成年哺乳动物轴突退缩的一种选择性机制。
