Ultrastructure and synaptic organization of the spinal accessory nucleus of the rat
Ultrastructure and synaptic organization of the spinal accessory nucleus of the rat
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大鼠脊髓副核的超微结构和突触组织
DOI：
10.1007/s00429-002-0248-7
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发表时间：
2002
期刊：
影响因子：
--
通讯作者：
M. Seki
中科院分区：
文献类型：
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作者：
T. Hayakawa;A. Takanaga;Koichii Tanaka;Seishi Maeda;M. Seki
副核由支配胸锁乳突肌的内侧柱神经元和支配阔肌的外侧柱神经元组成。我们逆行标记这些神经元注射霍乱毒素结合辣根过氧化物酶到胸锁乳突肌（SM）或锁骨（CT）肌肉，并研究这些神经元的精细结构和突触学。几乎所有的SM和CT运动神经元都有α运动神经元的外观，即，大的、椭圆形或多边形的细胞，含有发育良好的细胞器、尼氏体和突出的球形核。60%以上的体细胞膜被终末覆盖。SM运动神经元（34.4 × 52.2 µm，一个切片1，363.1 µ m2）略大于CT运动神经元（32.8 × 54.2 µm，1，180.8 µm2）。SM和CT运动神经元的轴体终末平均数分别为52.2和54.2。其中58.0%的细胞含有多形性小泡，与SM运动神经元形成对称性突触接触（Gray 'sII型），57.9%的细胞含有圆形小泡，与CT运动神经元形成不对称性突触接触（Gray' sI型）。在SM（3.5）和CT（3.7）运动神经元上存在少量C-终末。在SM和CT运动神经元中，约60%的轴树突终末为Gray Ⅰ型。在SM和CT运动神经元中也发现少量标记的小运动神经元。它们很小（19.2 × 26.2 µm，367.0 µm2），圆形细胞，细胞器发育不良，有一些轴体末端（9.3）。只有20%的体细胞膜被终末覆盖。因此，这些神经元被认为是γ-运动神经元。这些结果表明，副核内、外柱运动神经元具有不同的超微结构特征。
The accessory nucleus is composed of neurons in the medial column that innervate the sternocleidomastoid muscle, and neurons in the lateral column that innervate the trapezius muscle. We retrogradely labeled these neurons by injection of cholera toxin conjugated horseradish peroxidase into the sternomastoid (SM) or the clavotrapezius (CT) muscles, and investigated fine structure and synaptology of these neurons. Almost all SM and CT motoneurons had the appearance of α-motoneurons, i.e., large, oval or polygonal cells containing well-developed organelles, Nissl bodies, and a prominent spherical nucleus. More than 60% of the somatic membrane was covered with terminals. The SM motoneurons (34.4 × 52.2 µm, 1,363.1 µm2in a section) were slightly larger than the CT motoneurons (32.8 × 54.2 µm, 1,180.8 µm2). The average number of axosomatic terminals in a section was 52.2 for the SM, and 54.2 for the CT motoneurons. More than half of them (58.0%) contained pleomorphic vesicles and made symmetric synaptic contacts (Gray's type II) with the SM motoneurons, while 57.9% of them contained round vesicles and made asymmetric synaptic contacts (Gray's type I) with the CT motoneurons. A few C-terminals were present on the SM (3.5) and the CT (3.7) motoneurons. About 60% of the axodendritic terminals were Gray's type I in both the SM and the CT motoneurons. A few labeled small motoneurons were also found among the SM and the CT motoneurons. They were small (19.2 × 26.2 µm, 367.0 µm2), round cells containing poorly developed organelles with a few axosomatic terminals (9.3). Only 20% of the somatic membrane was covered with the terminals. Thus, these neurons were presumed to be γ-motoneurons. These results indicate that the motoneurons in the medial and the lateral column of the accessory nucleus have different ultrastructural characteristics.