Elucidation of target muscle and detailed development of dorsal motor neurons in chick embryo spinal cord.
Elucidation of target muscle and detailed development of dorsal motor neurons in chick embryo spinal cord.
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阐明鸡胚脊髓中的目标肌肉和背侧运动神经元的详细发育。
DOI：
10.1002/cne.23326
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发表时间：
2013
期刊：
影响因子：
--
通讯作者：
Yaginuma H.
中科院分区：
文献类型：
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作者：
Kobayashi N;Homma S;Okada T;Masuda T;Sato N;Nishiyama K;Sakuma C;Shimada T;Yaginuma H.
鸟类的颈髓包括运动神经元(MN)，它们通过背根发送轴突。它们被称为背侧运动神经元(DMN)，被认为对应于支配瓜状肌的副神经的MN(SAN-MN)。然而，到目前为止，他们的目标肌肉还没有被阐明。本研究试图确定DMNS和SAN-MNS表达的转录因子的靶点和特定的组合，并描述DMNS的详细发展。用追踪技术进行的实验证实，DMNS的轴突支配着葫芦肌。逆行标记的DMN分布于C3的前角及更多的尾段。在大多数情况下，在C2节段也可观察到一些DMN。本研究还证实了三叉神经核团存在于大鼠下丘脑C_1~2节段的前角及邻近的后脑尾侧。SAN-MNS和DMNS均表达Isl1，但不表达Isl2、MNR2或Lhx3。相反，这些MN表达PHOX2B，这是鳃运动神经元(BrMN)的标志，尽管表达强度较弱。背侧MNS和SAN-MNS来源于Nkx2.2阳性的前体结构域，并向背侧迁移。背侧MN保留在神经管的腹侧区域，不像脑干中的BrMN。这些结果表明，DMNS和SAN-MNS属于一个共同的支配葫芦肌的MN群体，也表明它们与脑干的BrMN相似，尽管在PHOX2B表达和每个群体的最终位置上存在差异。J.Comp.神经。2013年521：2987-3002。©2013 Wiley期刊，Inc.
The avian cervical spinal cord includes motoneurons (MNs) that send their axons through the dorsal roots. They have been calleddorsal motoneurons(dMNs) and assumed to correspond to MNs of the accessory nerve that innervate the cucullaris muscle (SAN‐MNs). However, their target muscles have not been elucidated to date. The present study sought to determine the targets and the specific combination of transcription factors expressed by dMNs and SAN‐MNs and to describe the detailed development of dMNs. Experiments with tracing techniques confirmed that axons of dMNs innervated the cucullaris muscle. Retrogradely labeled dMNs were distributed in the ventral horn of C3 and more caudal segments. In most cases, some dMNs were also observed in the C2 segment. It was also demonstrated that SAN‐MNs existed in the ventral horn of the C1–2 segments and the adjacent caudal hindbrain. Both SAN‐MNs and dMNs expressed Isl1 but did not express Isl2, MNR2, or Lhx3. Rather, these MNs expressed Phox2b, a marker for branchial motoneurons (brMNs), although the intensity of expression was weaker. Dorsal MNs and SAN‐MNs were derived from the Nkx2.2‐positive precursor domain and migrated dorsally. Dorsal MNs remain in the ventral domain of the neural tube, unlike brMNs in the brainstem. These results indicate that dMNs and SAN‐MNs belong to a common MN population innervating the cucullaris muscle and also suggest that they are similar to brMNs of the brainstem, although there are differences in Phox2b expression and in the final location of each population. J. Comp. Neurol. 521: 2987–3002, 2013. © 2013 Wiley Periodicals, Inc.