Firing and Cellular Properties of V2a Interneurons in the Rodent Spinal Cord
Firing and Cellular Properties of V2a Interneurons in the Rodent Spinal Cord
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DOI：
10.1523/jneurosci.4821-09.2010
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发表时间：
2010-01-06
影响因子：
5.3
通讯作者：
Kiehn, Ole
中科院分区：
文献类型：
--
作者：
Dougherty, Kimberly J.;Kiehn, Ole
先前的研究已经表明，一组位于腹侧的神经元，称为V2 a中间神经元，在维持运动节律性和确保运动期间适当的左右交替中起关键作用（Crone等人，2008年、2009年）。这些V2 a中间神经元表达转录因子Chx 10。本研究的目的是表征Chx 10-GFP小鼠中单个V2 a中间神经元的运动相关活动、其细胞特性及其详细的解剖属性。开发了一种去除背角的制备物，以允许沿着整个腰脊髓从V2 a中间神经元沿着进行视觉全细胞斑片记录，同时留下足够的脊髓完整以产生虚构的运动。在药物诱发的运动样活动中，大部分Chx 10细胞表现出与每个腰椎节段的屈肌或伸肌活动相关的节律性放电或膜电位波动。Chx 10细胞主要接受节律性兴奋性输入。Chx 10神经元表现出各种各样的放电和潜在的节律特性。然而，这些属性都没有明显相关的运动样活动期间观察到的节律性。在双重记录中，我们没有发现Chx 10神经元相互连接的证据。细胞内填充显示不同的投影模式，大多数Chx 10中间神经元是本地的中央模式发生器和运动神经元区域的脊髓和其他长的上升和/或下降分支的投影。这些数据与V2 a神经元在调节节段性左右交替和同侧运动神经元放电中具有作用，而对节律产生的影响很小是相容的。
Previous studies have shown that a group of ventrally located neurons, designated V2a interneurons, play a key role in maintaining locomotor rhythmicity and in ensuring appropriate left-right alternation during locomotion ( Crone et al., 2008, 2009). These V2a interneurons express the transcription factor Chx10. The aim of the present study was to characterize the locomotor-related activity of individual V2a interneurons, their cellular properties, and their detailed anatomical attributes in Chx10-GFP mice. A dorsal horn-removed preparation was developed to allow for visual whole-cell patch recordings from V2a interneurons along the entire lumbar spinal cord while at the same time leaving enough of the spinal cord intact to generate fictive locomotion. During drug-evoked locomotor-like activity, a large proportion of Chx10 cells showed rhythmic firing or membrane potential fluctuations related to either flexor or extensor activity in every lumbar segment. Chx10 cells received predominantly rhythmic excitatory input. Chx10 neurons displayed a wide variety of firing and potential rhythmogenic properties. However, none of these properties was obviously related to the observed rhythmicity during locomotor-like activity. In dual recordings, we found no evidence of Chx10 neuron interconnectivity. Intracellular fills revealed diverse projection patterns with most Chx10 interneurons being local with projections to the central pattern generator and motor neuron regions of the spinal cord and others with long ascending and/or descending branches. These data are compatible with V2a neurons having a role in regulating segmental left-right alternation and ipsilateral motor neuron firing with little effect on rhythm generation.