Stuesse S L, Cruce W L, Powell K S
J Comp Neurol. 1984 Jan 20;222(3):358-65. doi: 10.1002/cne.902220304.
Cranial nerves IX and X in frogs have been described as originating from a nuclear group referred to as the IX-X complex. We studied the central nervous system components of this complex in Rana pipiens and R. catesbiana by labeling peripheral branches of cranial nerves IX and X and identifying the central nervous system contributions of these branches. Various peripheral nerves (IX and the cardiac, gastric, pulmonary, and laryngeal branches of X) were identified and soaked in horseradish peroxidase (HRP). One to 2 weeks later, the frogs were killed and processed for HRP by the tetramethylbenzidine method. Glossopharyngeal efferents originated from a small ventrolateral cell group found at the level of IX root exit. Vagal efferents formed a single column of cells in a ventrolateral position from the level of the brainstem exist of the vagus nerve (approximately 2,000 micrometers above the obex) to 200 micrometers below the obex (values given are for an 80-g frog). This cell group was separate from and just caudal to efferent cells of the glossopharyngeal nerve. Within the vagal portion of the column, cells projecting through the gastric branch were found throughout the rostral-caudal extent of the nucleus. "Cardiac" cells tended to be more rostral than "pulmonary" cells, and both groups of cells were located in the middle of the nucleus. "Laryngeal" cells were located more caudally in the nucleus. This peripheral representation within the vagal nucleus corresponds more closely to the organization found in the mammalian nucleus ambiguus, rather than to the apparent lack of organization found in the mammalian dorsal motor nucleus. Afferents of IX and X entered slightly rostral to the ventral roots of their respective nerves and descended in two tracts. The majority entered the tractus solitarius and descended in a medial position to cervical spinal cord. A portion of the afferents from the vagus nerve crossed the midline in the lower myelencephalon just dorsal to the central canal and ascended a short distance on the contralateral side. Within the solitary tract, vagal afferents were located in a ventrolateral position as they descended to below the obex. Glossopharyngeal afferents filled the remainder of the tract. A smaller portion of afferents from both IX and X did not enter the solitary tract but descended in the spinal tract of V and the dorsolateral funiculus of the spinal cord (Lissauer's tract) to thoracic levels. Afferents of IX also formed a rostral bundle which extended in the solitary tract to the caudal metencephalon.
青蛙的第九和第十对脑神经被描述为起源于一个称为第九 - 第十复合体的核团。我们通过标记第九和第十对脑神经的外周分支，并确定这些分支对中枢神经系统的贡献，研究了北美豹蛙和牛蛙中该复合体的中枢神经系统组成部分。识别出各种外周神经（第九对脑神经以及第十对脑神经的心脏、胃、肺和喉部分支），并将其浸泡在辣根过氧化物酶（HRP）中。1至2周后，处死青蛙，并采用四甲基联苯胺法对其进行HRP处理。舌咽传出神经起源于在第九对脑神经根部出口水平发现的一个小的腹外侧细胞群。迷走神经传出神经在从迷走神经脑干出口水平（在闩上方约2000微米）到闩下方200微米的腹外侧位置形成单列细胞（给出的值适用于一只80克重的青蛙）。这个细胞群与舌咽神经的传出细胞分开，且恰好在其尾侧。在该细胞柱的迷走神经部分内，通过胃部分支投射的细胞在整个核的头 - 尾范围内都有发现。“心脏”细胞往往比“肺”细胞更靠头侧，且这两组细胞都位于核的中部。“喉”细胞位于核的更尾侧。迷走神经核内的这种外周表征与哺乳动物疑核中发现的组织更紧密对应，而不是与哺乳动物背运动核中明显缺乏组织的情况对应。第九和第十对脑神经的传入神经在其各自神经的腹根稍头侧进入，并分成两条束下行。大多数传入神经进入孤束，并在内侧位置下行至颈脊髓。来自迷走神经的一部分传入神经在延髓下部中央管背侧穿过中线，并在对侧上升一小段距离。在孤束内，迷走神经传入神经在下行至闩下方时位于腹外侧位置。舌咽神经传入神经充满了该束的其余部分。来自第九和第十对脑神经的一小部分传入神经没有进入孤束，而是在三叉神经脊髓束和脊髓背外侧索（利绍尔束）中下行至胸段水平。第九对脑神经的传入神经还形成一个头侧束，该束在孤束中延伸至脑桥尾侧。
