MULTIPLE INNERVATION OF TONIC ENDPLATES REVEALED BY ACTIVITY-DEPENDENT UPTAKE OF FLUORESCENT-PROBES
MULTIPLE INNERVATION OF TONIC ENDPLATES REVEALED BY ACTIVITY-DEPENDENT UPTAKE OF FLUORESCENT-PROBES
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DOI：
10.1038/314357a0
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发表时间：
1985-01-01
期刊：
影响因子：
64.8
通讯作者：
RICH, MM
中科院分区：
文献类型：
--
作者：
LICHTMAN, JW;WILKINSON, RS;RICH, MM
在脊椎动物神经系统的发育过程中，支配靶细胞的轴突数量普遍减少。这种现象，通常被称为突触消除，在发育中的抽动肌肉纤维的神经肌肉交界处得到了特别好的研究2，3：在一段时间的多神经元神经支配之后，轴突分支被收回，通常使每个抽动纤维终板只由一个轴突支配。在这里，我们描述了一种研究突触消除的HEW技术--活性介导的荧光探针摄取。这些探针选择性地、超临界地标记单个轴突的所有终末。这项技术在成年蛇和胚胎蛇身上被用来研究含有两种纤维类型的薄肌的神经支配模式：抽搐纤维，它是快速收缩的，具有传播的动作电位；和紧张性纤维，它是缓慢收缩的，缺乏动作电位。我们发现，抽动肌纤维如预期的那样，在发育过程中消除了所有的多神经元神经支配；相反，紧张性纤维终板在成年后仍保持多神经元神经支配。强直肌终板的多重神经支配的持续性可能与强直肌纤维缺乏动作电位活动有关。
During development of the vertebrate nervous system, there is a widespread reduction in the number of axons innervating target cells1. This phenomenon, often called synapse elimination, has been particularly well studied at the neuromuscular junction of developing twitch muscle fibres2,3: following a period of polyneuronal innervation, axonal branches are retracted, usually leaving each twitch fibre endplate innervated by only one axon. Here we describe a hew technique for the study of synapse elimination—activity-mediated uptake of fluorescent probes. These probes selectively and supravitally label all the terminals of individual axons. The technique is used here in adult and embryonic snakes to study the innervation pattern of a thin muscle containing two fibre types: twitch fibres, which are fast-contracting and have propagated action potentials, and tonic fibres, which are slow-contracting and lack action potentials. We find that twitch muscle fibres, as expected, eliminate all polyneuronal innervation during development; in contrast, tonic fibre endplates remain polyneuronally innervated into adulthood. The persistence of multiple innervation at tonic endplates may be related to the lack of action potential activity in tonic muscle fibres.