English A W
Department of Anatomy and Cell Biology, Emory University, Atlanta, Georgia 30322.
J Comp Neurol. 1990 Nov 1;301(1):104-13. doi: 10.1002/cne.903010110.
The innervation territories of the nerves to the gluteus maximus muscle were investigated in neonatal rats by using evoked electromyographic mapping techniques. Similar methods were employed to determine the terminal fields of individual motoneurons. Both at birth and after the period of neuromuscular synapse elimination, rat gluteus maximus is partitioned by its two muscle nerves. Each of these partitions is further divided into neuromuscular compartments by the primary branches of the muscle nerves. The terminal fields of individual motoneurons are about as well localized in early neonates as in 26 day-old animals. Intracellular records from gluteal muscle cells reveal that some myotubes in a narrow region near the center of the muscle receive inputs from both of the muscle nerves during the period of polyneuronal innervation. Such cross-compartmental innervation could be demonstrated only until the eighth postnatal day, even though polyneuronally innervated muscle cells were found as late as postnatal day 18. Analysis of the trajectories of individual axons filled with horseradish peroxidase indicates that they branch into only one primary branch of the nerves to gluteus maximus, both in newborn and 14 day-old pups. The innervation of gluteus maximus at birth is essentially restricted to neuromuscular compartments. Synapse elimination probably plays a minor role in establishing neuromuscular compartments.
采用诱发肌电图测绘技术，对新生大鼠臀大肌神经的支配区域进行了研究。运用类似方法确定单个运动神经元的终末场。在出生时以及神经肌肉突触消除期之后，大鼠臀大肌均由其两条肌肉神经分隔。这些分隔中的每一个又被肌肉神经的初级分支进一步划分为神经肌肉区室。单个运动神经元的终末场在早期新生儿中的定位与26日龄动物中的情况大致相同。来自臀肌细胞的细胞内记录显示，在多神经元支配期，肌肉中心附近狭窄区域的一些肌管接受来自两条肌肉神经的输入。这种跨区室支配直到出生后第8天才能被证实，尽管多神经元支配的肌肉细胞在出生后第18天仍能被发现。对用辣根过氧化物酶填充的单个轴突轨迹的分析表明，在新生和14日龄幼崽中，它们仅分支到臀大肌神经的一个初级分支。出生时臀大肌的支配基本上局限于神经肌肉区室。突触消除可能在建立神经肌肉区室中起次要作用。
