Synaptic competition and the persistence of polyneuronal innervation at frog neuromuscular junctions.
Synaptic competition and the persistence of polyneuronal innervation at frog neuromuscular junctions.
复制标题
突触竞争和青蛙神经肌肉接头处多神经元神经支配的持续性。
DOI：
10.1002/neu.480180405
复制
发表时间：
1987
期刊：
影响因子：
--
通讯作者：
Herrera,AA
中科院分区：
文献类型：
--
作者：
Werle,MJ;Herrera,AA
消除多神经元支配的机制进行了研究，通过相关的形态和生理的竞争神经末梢在确定的双重神经支配的神经肌肉接头缝匠肌的成年青蛙（蛙pipiens）。突触效能（每单位神经末梢长度的终板电位幅度）被认为反映了末梢竞争突触空间的能力。在相同的突触部位的两个终端的突触效力被发现是令人惊讶的是相等的，与33%的中位数差异。如果双神经支配的交界处随机神经支配的终端对具有相同的范围内的突触的效力，发现在单一神经支配的交界处在同一肌肉中，预计会有更多的变化。这一发现支持了这样的假设，即当竞争效能存在较大差异时，较弱的输入从双神经支配的连接中被消除，并且如果竞争效能相对相等，则两种输入都可能持续存在。我们还测试了，但没有找到支持的假设，空间接近竞争终端之间的竞争加剧了突触消除过程中的突触空间的竞争。
Mechanisms governing the elimination of polyneuronal innervation were examined by correlating the morphology and physiology of competing nerve terminals at identified dually innervated neuromuscular junctions in sartorius muscles of adult frogs (Rana pipiens). Synaptic efficacy (endplate potential amplitude per unit nerve terminal length) was presumed to reflect the ability of a terminal to compete for synaptic space. The synaptic efficacies of two terminals at the same synaptic site were found to be surprisingly equal, with a median difference of 33%. Much more variation would be expected if dually innervated junctions were randomly innervated by pairs of terminals having the same range of synaptic efficacy as that found at singly innervated junctions in the same muscle. This finding supports the hypothesis that the weaker input is elimianted from dually innervated junctions when there is a large discrepancy in competitive efficacy, and that both inputs may persist if competitive efficacies are relatively equal. We also tested but failed to find support for the hypothesis that spatial proximity between competing terminals intensifies competition for synaptic space during synapse elimination.