Donahue S P, English A W
Department of Anatomy and Cell Biology, Yerkes Regional Primate Research Center, Atlanta, Georgia 30322.
J Neurosci. 1989 May;9(5):1621-7. doi: 10.1523/JNEUROSCI.09-05-01621.1989.
The calf muscles of the rat hindlimb are composed of smaller entities, called neuromuscular compartments, which are the territories of muscle innervated by a single, naturally occurring primary (first-order) muscle nerve branch. While it is quite clear that a precise connectivity exists very early in development between motoneuron pools and individual muscles, the mechanisms responsible for producing the adult pattern of compartmental innervation are unknown. This study uses intracellular recording techniques to demonstrate that neuromuscular compartments are essentially established at birth and that postnatal synapse elimination has little role in establishing neuromuscular compartments. Our results demonstrate the existence of a small number of cross-compartmental connections in neonates which are not present in adults. Examining the removal of these cross-compartmental connections in both normal muscles and in muscles that have had synapse elimination delayed by tenotomy reveals that the synapses responsible for this innervation are eliminated in a selective manner.
大鼠后肢的小腿肌肉由较小的实体组成，称为神经肌肉区室，它们是由单一自然存在的初级（一级）肌肉神经分支所支配的肌肉区域。虽然很明显运动神经元池与单个肌肉之间在发育早期就存在精确的连接，但产生成年期区室化神经支配模式的机制尚不清楚。本研究使用细胞内记录技术来证明神经肌肉区室在出生时基本就已形成，并且出生后突触消除在建立神经肌肉区室方面作用不大。我们的结果表明，新生儿中存在少量成年动物中不存在的跨区室连接。研究正常肌肉以及通过切断术使突触消除延迟的肌肉中这些跨区室连接的消除情况发现，负责这种神经支配的突触是以一种选择性方式被消除的。
