Developmental reorganization of the output of a GABAergic interneuronal circuit.
Developmental reorganization of the output of a GABAergic interneuronal circuit.
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GABA 能间神经元回路输出的发育重组。
DOI：
10.1152/jn.01324.2006
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发表时间：
2007
影响因子：
2.5
通讯作者：
Wenner,Peter
中科院分区：
文献类型：
--
作者：
Xu,Huaying;Clement,Arthur;Wright,TerrenceMichael;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。在这篇报道中，我们证明了GABA能R-中间神经元回路在胚胎第8天和第15天(E8和E15)的鸡胚胎脊髓中经历了重组。R-中间神经元接受运动神经元的突触输入，并投射回运动神经元。通过刺激投射到一个腹根的运动神经元和记录相邻节段运动神经元的双突触反应，我们证明了R中间神经元回路的输出在发育过程中发生了重组。刺激LS2腹根后，LS3运动神经元在全细胞记录中观察到的双突触反应变得更加常见和强烈，而较远的LS4运动神经元从E8到E10则较少见。光学研究表明，刺激LS2激活的R-中间神经元仅限于LS2节段，在E8和E10处都有少量谷氨酸能成分，但E10激活了更多的R-中间神经元。在E10招募更多的LS2 R中间神经元可能有助于向LS3运动神经元进行更强的投射，但接受这种输入的LS4运动神经元较少的事实与GABA能R中间神经元更远的投射的功能细化更一致。有趣的是，这种重组模式并没有在整个脊髓的肩尾范围内观察到，这引入了一种可能性，即改进可能有助于消除功能无关的中间神经元和运动神经元之间的联系。
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 report we demonstrate that the GABAergic R-interneuron circuit undergoes a reorganization in the chick embryo spinal cord between embryonic days 8 and 15 (E8 and E15). R-interneurons receive synaptic input from and project back to motoneurons. By stimulating motoneurons projecting in one ventral root and recording the disynaptic response from motoneurons in adjacent segments, we show that the output of the R-interneuron circuit is reorganized during development. After stimulation of the LS2 ventral root, disynaptic responses observed in whole cell recordings became more common and stronger for LS3 motoneurons and less common for the more distant LS4 motoneurons from E8 to E10. Optical studies demonstrated that R-interneurons activated by LS2 stimulation were restricted to the LS2 segment and had a small glutamatergic component at both E8 and E10, but that more R-interneurons were activated within the segment by E10. The recruitment of more LS2 R-interneurons at E10 is likely to contribute to stronger projections to LS3 motoneurons, but the fact that fewer LS4 motoneurons receive this input is more consistent with a functional refinement of the more distant projection of the GABAergic R-interneuron. Interestingly, this pattern of reorganization was not observed throughout the rostrocaudal extent of the cord, introducing the possibility that refinement could serve to remove connections between functionally unrelated interneurons and motoneurons.