Development of an inhibitory interneuronal circuit in the embryonic spinal cord.
Development of an inhibitory interneuronal circuit in the embryonic spinal cord.
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胚胎脊髓中抑制性中间神经元回路的发育。
DOI：
10.1152/jn.01091.2004
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发表时间：
2005
期刊：
影响因子：
--
通讯作者：
Wenner,Peter
中科院分区：
文献类型：
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作者：
Xu,Huaying;Whelan,PatrickJ;Wenner,Peter
局部投射抑制性中间神经元在网络活动的模式和时间安排中起着至关重要的作用。然而，由于它们相对难以接近，人们对它们的发展或融入电路知之甚少。在这项研究中，我们描述了发育过程中一个这样的脊髓神经元间回路的功能起始、神经递质、肩尾扩散和索状分布。R-中间神经元是哺乳动物Renshaw细胞的鸟类同系物。这两种类型的细胞都接受运动神经元经常性侧支的输入，并直接连接回运动神经元。通过刺激投射在给定腹根的运动神经元并记录相邻腹根的反应，我们证明了R中间神经元回路在胚胎第6天(E6)到E7开始起作用。这种腹根反应在E11和E14观察到，直到E16不再能检测到为止。使用BASH应用的神经递质受体拮抗剂，我们能够证明从e7.5到e15的回路主要是尼古丁和GABA能的。我们还在整个发育过程中发现了该途径的一个谷氨酸能成分。R中间神经元通过腹外侧索向吻侧和尾侧投射三个或三个以上节段。在e7.5和e15之间，该电路的分布可能变得更加局部集中。
Locally projecting inhibitory interneurons play a crucial role in the patterning and timing of network activity. However, because of their relative inaccessibility, little is known about their development or incorporation into circuits. In this study, we characterized the functional onset, neurotransmitters, rostrocaudal spread, and funicular distribution of one such spinal interneuronal circuit during development. The R-interneuron is the avian homologue of the mammalian Renshaw cell. Both cell types receive input from motoneuron recurrent collaterals and make direct connections back onto motoneurons. By stimulating motoneurons projecting in a given ventral root and recording the response in adjacent ventral roots, we demonstrate that the R-interneuron circuit becomes functional between embryonic day 6 (E6) and E7. This ventral root response is observed at E11 and at E14 until it can no longer be detected at E16. Using bath-applied neurotransmitter receptor antagonists, we were able to demonstrate that the circuit is predominately nicotinic and GABAergic from E7.5 to E15. We also found a glutamatergic component to the pathway throughout this developmental period. The R-interneuron projects three or more segments both rostrally and caudally through the ventrolateral funiculus. The distribution of this circuit may become more locally focused between E7.5 and E15.