Narusawa M
Tokai J Exp Clin Med. 1985 Oct;10(5):499-507.
In 30% or less partially denervated muscle, the reinnervation of denervated muscle fiber may give rise to a change in motor unit size or number of muscle fibers innervated by a single motor neuron. This study was designed to evaluate changes in fiber type and contractibility of partially denervated rat soleus muscle. Partial denervation (by 30% or less) of the soleus nerve does not cause a decrease in the number of muscle fibers. A histochemical study was performed on frozen sections of the muscle. The total number of muscle fibers, atrophied fibers and type II fibers were counted. In the muscle 4 weeks after partial denervation, the number of type II fibers was fewer with a decrease of about 40% which was not significant. The twitch time to peak and half-relaxation time were not changed. The number of type II fibers was significantly decreased (p less than 0.01) after 8 weeks. There was a prolongation of contraction time. The decrease of type II fibers was extensive involving not only the denervated area but also the rest of the muscle area. The transformation of fiber type observed in partially denervated muscle may be attributed to a possible diminution of neurotrophic substances in intact motor neurons.
在30%或更少部分失神经支配的肌肉中，失神经支配肌纤维的重新神经支配可能导致运动单位大小或单个运动神经元支配的肌纤维数量发生变化。本研究旨在评估部分失神经支配的大鼠比目鱼肌的纤维类型和收缩性变化。比目鱼神经的部分失神经支配（30%或更少）不会导致肌纤维数量减少。对肌肉的冰冻切片进行了组织化学研究。计算了肌纤维总数、萎缩纤维和II型纤维的数量。在部分失神经支配4周后的肌肉中，II型纤维数量减少，减少约40%，但不显著。抽搐达到峰值的时间和半松弛时间未改变。8周后，II型纤维数量显著减少（p小于0.01）。收缩时间延长。II型纤维的减少广泛，不仅涉及失神经支配区域，还涉及肌肉的其余区域。在部分失神经支配的肌肉中观察到的纤维类型转变可能归因于完整运动神经元中神经营养物质的可能减少。
