Wenner P, O'Donovan M J
Section on Developmental Neurobiology, Laboratory of Neural Control, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland 20892-4455, USA.
J Neurosci. 1999 Sep 1;19(17):7557-67. doi: 10.1523/JNEUROSCI.19-17-07557.1999.
Studies on the development of synaptic specificity, embryonic activity, and neuronal specification in the spinal cord have all been limited by the absence of a functionally identified interneuron class (defined by its unique set of connections). Here, we identify an interneuron population in the embryonic chick spinal cord that appears to be the avian equivalent of the mammalian Renshaw cell (R-interneurons). These cells receive monosynaptic nicotinic, cholinergic input from motoneuron recurrent collaterals. They make predominately GABAergic connections back onto motoneurons and to other R-interneurons but project rarely to other spinal interneurons. The similarity between the connections of the developing R-interneuron, shortly after circuit formation, and the mature mammalian Renshaw cell raises the possibility that R-interneuronal connections are formed precisely from the onset. Using a newly developed optical approach, we identified the location of R-interneurons in a column, dorsomedial to the motor nucleus. Functional characterization of the R-interneuron population provides the basis for analyses that have so far only been possible for motoneurons.
脊髓中突触特异性、胚胎活动和神经元特化的研究一直受到缺乏功能明确的中间神经元类别的限制（由其独特的连接组定义）。在这里，我们在胚胎鸡脊髓中鉴定出一个中间神经元群体，它似乎相当于哺乳动物的闰绍细胞（R-中间神经元）。这些细胞接受来自运动神经元回返侧支的单突触烟碱能胆碱能输入。它们主要与运动神经元和其他R-中间神经元形成GABA能连接，但很少投射到其他脊髓中间神经元。在回路形成后不久，发育中的R-中间神经元的连接与成熟哺乳动物闰绍细胞之间的相似性增加了R-中间神经元连接从一开始就精确形成的可能性。使用新开发的光学方法，我们确定了R-中间神经元在运动核背内侧柱中的位置。R-中间神经元群体的功能特征为迄今为止仅针对运动神经元进行的分析提供了基础。
