大鼠三叉神经中脑核神经元中枢突的行径和分布—HRP跨节追踪研究

DISTRIBUTION AND COURSE OF THE CENTRAL PROCESSES OF THE TRIGEMINAL MESENCEPHALIC NUCLEUS IN THE RAT——HRP TRANSGANGLIONIC TRACING METHOD

将HRP注入大鼠咬肌神经干,在同侧的半月节、咬肌神经核、三叉神经中脑核、三叉上核等处出现标记细胞。大量的跨节标记的中脑核神经元中枢突在同侧Probst束内下降,除一般所记载的Probst束的起始段外,由Ⅶ核水平向尾侧也清楚地看到了此束的范围逐渐缩小且由较疏散的小束组成,位于桥、延网状结构的背外侧部,下可达颈髓上段。此束在走行中,其纤维除终止于咀嚼核、三叉上核外,左面神经核水平有浓密的标记终末止于桥脑网状结构背外侧部的特定部分,形成外、内两簇标记终末群。此区曾有人称为Probst核,但在构筑学上未发现有明确的特征。中脑核神经元中枢突大量终止于此,它有何意义尚有待进一步探索。此外,此束的纤维还分布于孤束核、舌下神经核、颈髓上段后角同Ⅴ-Ⅵ层等处,特别是所有实验例的吻侧疑核处均出现浓密的标记终末。咬肌神经内来自肌梭以外的传入神经元在下颌节的胞体被标记,其中枢突进入脊束背侧部下行,在三叉脊束核尾侧亚核的Ⅰ、Ⅱ重层出现少量标记终末,并有极少量纤维通往Ⅴ、Ⅵ层。

HRP was injected into the masseter nerve of the rat.Labeled cells in the masseter nucleus,trigeminal mesencephalic nucleus,(Vmes),semilunar ganglion(VG),supratrigeminal nucleus(Vsup)were observed ipsilaterally.Transganglionically labeled central processes of Vmes-neurons were seen to descend ipsilaterally in the Probst tract(Pt),this tract was located in the lateral part of the reticular formation of the pons and medulla oblongata,i.e.,ventral to the vestibular nuclear complex,dorsomedial to the trigeminal spinal nuclei and ventrolateral to the solitary tract nucleus(Sol),and these fibers were seen to end in laminaeⅤ-Ⅵof the upper segments of the cervical cord.Profuse la-beled fibers were found to end in the masticatory nucleus(Vm),Vsup,Probst nucleus(Pn),oral part of ambiguus nucleus(O.am),and the dor-solateral part of the reticular formation of the pons and medulla oblon-gata.Moderately labeled terminals were observed in the trigeminal spinal nuclei(Vsp),i.e.,the trigeminal spinal caudal nucleus(Vc),trigeminal spinal interpolar nucleus(Vi),trigeminal spinal oral nucleus(Vo),and laminaeⅤ-Ⅵof the upper segments of the cervical cord.A few labeled fibers were found in the hypoglossal nucleus(Ⅶ),and the Sol.The name of Pn has not been described in literature except Matesz,so the form and property of it is discussed in the present study.The relation of the oral part of O am to Pt is not mentioned by other researchers up to now.Labeled Vmes cells were scattered throughout the whole rostro-caudal extent of the nueleus,and most of them were in the widened pontine part of the Vmes.Transganglionically labeled central processcs of the mandibular division of the VG neurons wcre observed to descend ipsilaterally in the mandibular division of the trigeminal spinal tract(Vspt),these fibers were found to end in laminaeⅠ-Ⅱof the Vc and penetrate into laminaeⅤ-Ⅵof the upper segments of the cervical cord.