TOPOGRAPHICALLY ORGANIZED PROJECTIONS FROM THE NUCLEUS SUBCERULEUS TO THE HYPOGLOSSAL NUCLEUS IN THE RAT - A LIGHT AND ELECTRON-MICROSCOPIC STUDY WITH COMPLEMENTARY AXONAL-TRANSPORT TECHNIQUES
TOPOGRAPHICALLY ORGANIZED PROJECTIONS FROM THE NUCLEUS SUBCERULEUS TO THE HYPOGLOSSAL NUCLEUS IN THE RAT - A LIGHT AND ELECTRON-MICROSCOPIC STUDY WITH COMPLEMENTARY AXONAL-TRANSPORT TECHNIQUES
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DOI：
10.1002/cne.903020318
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发表时间：
1990-12-15
影响因子：
2.5
通讯作者：
ALDES, LD
中科院分区：
文献类型：
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作者：
ALDES, LD
用互补逆行和顺行轴突运输技术，在光镜和电子显微镜水平上研究了大鼠蓝下核(NSC)向舌下核(XII)的投射。将WGA-HRP注射到XII可引起NSC内及周围神经元的标记。标记的NSC神经元数量少(每40-60微米切片4个)，大小和形状不同。大多数标记的NSC神经元为中等大小(X=16.89微米)，梭形、三角形或椭圆形，3-4个树突通常定向于背内侧和腹侧。这些神经元遍布神经干细胞的吻尾部，但在三叉神经运动核的内侧、背内侧和腹内侧最多。另一些则位于三叉神经运动核的吻侧和臂旁核复合体的腹侧。在向NSC注射氚氨基酸或WGA-HRP后，逆行结果得到确认。这导致了XII吻尾范围内的标记，主要是同侧。标记纤维下行至脑干的背外侧部，少量分布于普罗布斯特‘’S束的腹内侧部。纤维主要沿核的外侧缘在吻侧进入。XII的所有区域都是NSC传入的受体，但尾腹内侧象限的终末标记密度最高。电子显微镜观察证实，NSC传入神经元在XII区的运动神经元上有突触。含有WGA-HRP反应产物的轴突终末可与树突和胞体接触，但以前者为主(81.3%对10.6%)。轴突终末主要突触在中、小型树突上(直径3微米)。大多数标记的轴突终末(90.1%)含有小而圆且清晰的突触小泡(S型：20~50 nm)，并与不对称(60.6%)、对称(11.4%)或无(18%)突触后特化有关。相反，大多数轴体终末含有扁平的小泡(F型)，并形成对称性或无突触后特化(75%)。少数(1.3%)标记轴突终末内可见大而致密的核心小泡(55~90 nm)。本研究结果表明，NSC投射到XII，优先靶向特定亚群的突触运动神经元，突触位于胞体和树突上，但主要投射于树突。这些数据的放大是与舌头控制相关的讨论。
Projections from the nucleus subceruleus (nSC) to the hypoglossal nucleus (XII) were investigated with complementary retrograde and anterograde axonal transport techniques at the light and electron microscopic level in the rat. Injections of WGA-HRP into XII resulted in labeling of neurons in and around the nSC. Labeled nSC neurons were few in number (< 4 per 40-60 .mu.m sections) and variable in size and shape. Most labeled nSC neurons were medium-sized (.hivin.X = 16.89 .mu.m), fusiform, triangular, or oval, with 3-4 dendrites typically oriented dorsomedially and ventrolaterally. These neurons were found throughout the rostrocaudal extent of the nSC but were most numerous medial, dorsomedial, and ventromedial to the motor trigeminal nucleus. Others were observed rostral to the motor trigeminal nucleus and ventral to the parabrachial nuclear complex. Confirmation of retrograde results was obtained following injections of tritiated amino acids or WGA-HRP into the nSC. This resulted in labeling throughout the rostrocaudal extent of XII mainly ipsilaterally. Labeled fibers descended the brainstem in the dorsolateral and, to a lesser extent, in the ventromedial component of Probst''s tract. Fibers entered XII mainly rostrally along the lateral border of the nucleus. All regions of XII were recipients of nSC afferents, but the caudoventromedial quadrant contained the greatest density of terminal labeling. Electron microscopic evaluation confirmed that nSC afferents synapsed on motoneurons in XII. Axon terminals containing WGA-HRP reaction product were found contactting dendrites and somata, but primarily the former (81.3% versus 10.6%). Axondendritic terminals synapsed mainly on medium-to-small sized dendrites (< 3 .mu.m in diameter). The majority of labeled axodendritic terminals (90.1%) contained small, round, and clear synaptic vesicles (S-type: 20-50 nm) and were associated with an asymmetric (60.6%), symmetric (11.4%), or no (18%) postsynaptic specialization. By contrast, most axosomatic terminals contained flattened vesicles (F-type) and formed a symmetric or no postsynaptic specialization (75%). Large dense core vesicles (55-90 nm) were observed within a small proportion of all labeled axon terminals (1.3%). The results from this study demonstrate that the nSC projects to XII, preferentially targets a specific subgrouping of protrusor motoneurons, and synapses on both somata and dendrites, although mainly on the latter. The amplications of these data are discussed relative to tongue control.