Characterization of Last-Order Premotor Interneurons by Transneuronal Tracing With Rabies Virus in the Neonatal Mouse Spinal Cord
Characterization of Last-Order Premotor Interneurons by Transneuronal Tracing With Rabies Virus in the Neonatal Mouse Spinal Cord
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DOI：
10.1002/cne.22717
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发表时间：
2011-12-01
影响因子：
2.5
通讯作者：
Vinay, Laurent
中科院分区：
文献类型：
--
作者：
Coulon, Patrice;Bras, Helene;Vinay, Laurent
我们通过使用狂犬病病毒的逆行跨神经元追踪，对小鼠新生儿腰椎增大中参与控制踝伸肌三头肌 [TS] 肌肉）运动神经元 MN）的中间神经元进行了表征。对接种后连续时间间隔的逆行跨神经元转移动力学的检查使我们能够确定仅一级中间神经元（即可能与 MN 最后级中间神经元 [loINs]）单突触连接的中间神经元被 RV 感染的时间窗口。该网络的感染完全是由于 RV 沿着运动通路逆行运输所致。大约 80% 的 loIN 是在注射同侧观察到的。它们沿着腰椎增大分布，但大多数观察到 TS MN 位于 L4 和 L5 节段。大多数 loIN 分布在 V-VII 层，而最表层的层没有 RV 感染。相反，在所有腰椎节段的第 VIII 层中均发现了连合腰椎。使用双重免疫标记对 loIN 组进行化学表型表征。连接到 TS MN 的甘氨酸能神经元占同侧 loIN 的 50%，占对侧 loIN 的 10%。正如预期的那样，同侧甘氨酸能 loIN 包括 Renshaw 细胞，即表达钙结合蛋白的最腹侧神经元。我们还证明了在 L3 和 L4 的喙部同侧观察到的一组胆碱能中间神经元与 TS MN 之间的直接联系。总之，RV 跨神经元追踪与神经元决定因素的免疫组织化学检测相结合，可以对参与单个肌肉控制的运动网络进行非常具体的绘图。 J.Comp。内罗尔。 519:3470-3487, 2011。(C) 2011 Wiley-Liss, Inc.
We characterized the interneurons involved in the control of ankle extensor triceps surae [TS] muscles) motoneurons MNs) in the lumbar enlargement of mouse neonates by retrograde transneuronal tracing using rabies virus RV). Examination of the kinetics of retrograde transneuronal transfer at sequential intervals post inoculation enabled us to determine the time window during which only the first-order interneurons, i.e., interneurons likely monosynaptically connected to MNs last-order interneurons [loINs]) were RV-infected. The infection of the network resulted exclusively from a retrograde transport of RV along the motor pathway. About 80% of the loINs were observed ipsilaterally to the injection. They were distributed all along the lumbar enlargement, but the majority was observed in L4 and L5 segments where TS MNs were localized. Most loINs were distributed in laminae V-VII, whereas the most superficial laminae were devoid of RV infection. Contralaterally, commissural loINs were found essentially in lamina VIII of all lumbar segments. Groups of loINs were characterized by their chemical phenotypes using dual immunolabeling. Glycinergic neurons connected to TS MNs represented 50% of loINs ipsilaterally and 10% contralaterally. As expected, the ipsilateral glycinergic loINs included Renshaw cells, the most ventral neurons expressing calbindin. We also demonstrated a direct connection between a group of cholinergic interneurons observed ipsilaterally in L3 and the rostral part of L4, and TS MNs. To conclude, transneuronal tracing with RV, combined with an immunohistochemical detection of neuronal determinants, allows a very specific mapping of motor networks involved in the control of single muscles. J. Comp. Neurol. 519:3470-3487, 2011. (C) 2011 Wiley-Liss, Inc.