The central projection of masticatory afferent fibers to the trigeminal sensory nuclear complex and upper cervical spinal cord
The central projection of masticatory afferent fibers to the trigeminal sensory nuclear complex and upper cervical spinal cord
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DOI：
10.1002/cne.902680403
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发表时间：
1988-02
影响因子：
2.5
通讯作者：
Y. Shigenaga;Masayuki Sera;T. Nishimori;S. Suemune;M. Nishimura;A. Yoshida;Koichi Tsuru
中科院分区：
文献类型：
--
作者：
Y. Shigenaga;Masayuki Sera;T. Nishimori;S. Suemune;M. Nishimura;A. Yoshida;Koichi Tsuru
辣根过氧化物酶-麦胚凝集素（HRP-WGA）结合物的逆行和顺行运输用于研究支配咀嚼肌的初级传入神经元的组织。HRP应用于三叉神经节和中脑三叉神经核（Vmes）中的颞深肌（DT）、咬肌（Ma）和翼内肌（MP）标记细胞，而HRP应用于三叉神经节中的开颌肌神经-前二腹肌（AD）和下颌舌骨肌（My）标记细胞。在下颌骨亚部的中间区域发现了支配下颌闭合肌的细胞体的频率更高，而供应下颌张开肌的细胞体主要位于后外侧。其体细胞大小的分布是单峰的，并限于一个较小的细胞亚群。三叉神经感觉核复合体（TSNC）的神经节起源的肌肉传入的投射主要局限于极间部（Vi）的尾侧半，以及延髓和上颈后角。在Vi、Ma、MP、AD和My神经中，除了投射到间质核或三叉旁核的DT神经外，其终止于核的最外侧部分，投射广泛重叠。在延髓和上颈后角，各分支的主要终末野局限于I/V层，但V层的终末密度很稀疏。的rostrocaudal程度的终端领域在板I不同的肌肉传入的起源，而在mediolateral或背腹轴，一个显着的重叠，在预测之间或肌肉传入。DT传入神经的终末最广泛地从尾侧部的吻侧水平延伸到C3段，而MP神经显示出有限的投射到尾侧部的中间三分之一。Ma、AD和My神经的终末野分别出现在尾状部的尾侧三分之二，包括前两个颈段、尾状部的尾侧半部分和C1段，以及尾状部的尾侧部分，包括喙侧C1段。肌肉神经投射中的这种喙尾排列，对应于肌肉的前后长度及其位置，表明咀嚼肌在第I层中的表现反映了洋葱皮组织。这些结果表明，神经节起源的初级肌肉传入神经元主要介导肌肉疼痛。此外，还观察了闭颌肌传入神经元在三叉神经中脑核（Vmes）的分布及其中枢投射。来自DT和Ma神经的Vmes神经元呈双峰分布，在核的喙1半中具有较大数量，而来自MP神经的Vmes神经元稀疏且均匀分布。支配三块闭颌肌的Vmes神经元的单个中央轴突投射到三叉神经运动核（Vmo）、三叉神经上区和三叉神经间区，以及延伸到脊髓上部的延髓外侧网状结构。然而，有差异的轴突从不同的肌肉的尾部范围。
Retrograde and anterograde transport of horseradish peroxidase‐wheat germ agglutinin (HRP‐WGA) conjugate was used to study the organization of primary afferent neurons innervating the masticatory muscles. HRP applied to the nerves of jaw‐closing muscles–the deep temporal (DT), masseter (Ma), and medial pterygoid (MP)–labeled cells in the trigeminal ganglion and the mesencephalic trigeminal nucleus (Vmes), whereas HRP applied to nerves of the jaw‐opening muscles–anterior digastric (AD) and mylohyoid (My)–labeled cells only in the trigeminal ganglion. Cell bodies innervating the jaw‐closing muscles were found with greater frequency in the intermediate region of the mandibular subdivision, while somata supplying the jaw‐opening muscles were predominant posterolaterally. The distribution of their somatic sizes was unimodal and limited to a subpopulation of smaller cells. Projections of the muscle afferents of ganglionic origin to the trigeminal sensory nuclear complex (TSNC) were confined primarily to the caudal half of pars interpolaris (Vi), and the medullary and upper cervical dorsal horns. In the Vi, Ma, MP, AD, and My nerves terminated in the lateral‐most part of the nucleus with an extensive overlap in projections, save for the DT nerve, which projected to the interstitial nucleus or paratrigeminal nucleus. In the medullary and upper cervical dorsal horns, the main terminal fields of individual branches were confined to laminae I/V, but the density of the terminals in lamina V was very sparse. The rostrocaudal extent of the terminal field in lamina I differed among the muscle afferents of origin, whereas in the mediolateral or dorsoventral axis, a remarkable overlap in projections was noted between or among muscle afferents. The terminals of DT afferents were most broadly extended from the rostral level of the pars caudalis to the C3 segment, whereas the MP nerve showed limited projection to the middle one‐third of the pars caudalis. Terminal fields of the Ma, AD, and My nerves appeared in the caudal two‐thirds of the pars caudalis including the first two cervical segments, the caudal half of the pars caudalis and the C1 segment, and in the caudal part of the pars caudalis including the rostral C1 segment, respectively. This rostrocaudal arrangement in the projections of muscle nerves, which corresponds to the anteroposterior length of the muscles and their positions, indicates that representation of the masticatory muscles in lamina I reflects an onion‐skin organization. These results suggest that primary muscle afferent neurons of ganglionic origin primarily mediate muscle pain. In addition, the distribution patterns of the afferent neurons of jaw‐closing muscles in the mesencephalic trigeminal nucleus (Vmes) and their central projections were examined. The Vmes neurons from the DT and Ma nerves were bimo‐dally distributed, with larger numbers in the rostra1 half of the nucleus, whereas those from the MP nerve were sparsely and evenly distributed. Individual central axons of the Vmes neurons innervating the three jaw‐closing muscles projected to the trigeminal motor nucleus (Vmo), supra‐ and intertrigeminal regions, and lateral reticular formation of the medulla extending to the upper spinal cord. There were, however, differences in the caudal extent of the axons from the different muscles.