ORGANIZATION AND NEUROCHEMICAL PROPERTIES OF INTERSEGMENTAL INTERNEURONS IN THE LUMBAR ENLARGEMENT OF THE ADULT RAT
ORGANIZATION AND NEUROCHEMICAL PROPERTIES OF INTERSEGMENTAL INTERNEURONS IN THE LUMBAR ENLARGEMENT OF THE ADULT RAT
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DOI：
10.1016/j.neuroscience.2010.09.012
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发表时间：
2010-12-01
期刊：
影响因子：
3.3
通讯作者：
Maxwell, D. J.
中科院分区：
文献类型：
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作者：
Liu, T. T.;Bannatyne, B. A.;Maxwell, D. J.
轴突相对较短的节间中间神经元在肢体运动的协调中发挥着重要作用，但令人惊讶的是，人们对它们的组织以及它们如何对成年大鼠的神经元网络做出贡献知之甚少。我们进行了一系列解剖束追踪研究，以标记腰脊髓节间神经元的细胞体和轴突，并使用免疫细胞化学表征其神经化学特性。内侧运动核 在 L5 腰椎节段中，分别注射到外侧运动核和内侧运动核后，发现细胞集中在对侧第 VIII 层以及同侧第 VII 层和第 VVI 层。大约 25% 的标记细胞含有钙结合蛋白或钙结合蛋白或两种钙结合蛋白阳性细胞的组合，主要分布在 L5 节段的同侧，特别是同侧背角内，而是对侧 VIII 层中钙视网膜素细胞的浓度 中央管周围的一小群细胞是胆碱能的 我们还检查了从 L1/3 投射到 L5 对侧外侧运动核的轴突末端 这些轴突中的大多数是兴奋性的 (75%) 并与运动神经元直接接触 然而，L5 中的大多数抑制性轴突含有 GABA 和甘氨酸的混合物 (20%)，约占总细胞数的 22%相比之下，L3 对侧外侧运动核中所有节段内轴突的 19% 被发现是纯粹的甘氨酸能，17% 含有 GABA 和甘氨酸的混合物。这项研究表明，短程中间神经元在腰椎增大内形成广泛的同侧和对侧投射，其中许多含有钙结合蛋白。那些投射到运动核对侧的主要是兴奋性的 (C) 2010 IBRO 爱思唯尔有限公司出版版权所有
Intersegmental interneurons with relatively short axons perform an important role in the coordination of limb movement but surprisingly little is known about their organization and how they contribute to neuronal networks in the adult rat We undertook a series of anatomical tract tracing studies to label cell bodies and axons of intersegmental neurons in the lumbar cord and characterized their neurochemical properties by using immunocytochemistry The b sub unit of cholera toxin was injected into L1 or L3 segments of seven rats in the vicinity of lateral or medial motor nuclei In L5 lumbar segments, cells were found to be concentrated in contralateral lamina VIII and in ipsilateral lamina VII and laminae V VI following injections into the lateral and medial motor nuclei respectively About 25% of labelled cells con tamed calbindin or calretinin or a combination of both Calbindin positive cells ware mainly distributed within the ipsilateral side of the L5 segment, especially within the ipsilateral dorsal horn whereas there was a concentration of calretinin cells in contralateral lamina VIII A small population of cells around the central canal were cholinergic We also examined axon terminals that projected from L1/3 to the L5 contralateral lateral motor nucleus The majority of these axons were excitatory (75%) and made direct contacts with motoneurons However, most inhibitory axons in L5 contained a mixture of GABA and glycine (20%) and about 22% of the total population of axons contained calbindin In contrast 19% of all intra segmental axons in the L3 contralateral lateral motor nucleus were found to be purely glycinergic and 17% con tamed a mixture of GABA and glycine This study shows that short range interneurons form extensive ipsi and contralateral projections within the lumbar enlargement and that many of them contain calcium binding proteins Those projecting contralaterally to motor nuclei are predominantly excitatory (C) 2010 IBRO Published by Elsevier Ltd All rights reserved