三叉神经躯体传入成分向孤束核投射的间接途径—HRP跨节和逆行追踪技术的光镜和电镜研究

THE INDIRECT PATHWAY OF THE SOMATIC AFFERENT ELEMENTS FROM TRIGEMINAL NERVE TO NUCLEUS TRACTUS SOLITARII——A LIGHT AND ELECTRON MICROSCOPIC HRP TRANSGANGLIONIC AND RETROGRADE TRACING STUDY

用HRP跨节及逆行追踪的光镜和电镜技术探索了三叉神经(TGN)躯体性传入成分向孤束核(NTS)的间接投射通路。HRP微量注射于闩平面的NTS后,逆行标记细胞出现于与TGN尾侧亚核背外部邻接的脊束内的间质核。同时,此核又是TGN的舌神经和眶下神经初级传入的投射部位。电镜观察发现,HRP标记的舌神经和眶下神经初级传入终末与间质核内神经元的树突形成较多的突触连接。有部分标记终末与向NTS投射的神经元的逆行标记树突和树突棘在间质核内形成突触连接。另外,本文研究证明,间质核和TGN尾侧亚核浅层的细胞构筑基本相同,且有些间质核的细胞团系由尾侧亚核浅层结构向脊束内突入而形成,故可将两者视为一个统一体。据此,本文作者认为,TGN和NTS之间存在着经间质核中继的两级神经元传入通路,经此通路传入的冲动应属于躯体性质。推测由两级神经元组成的这个通路可能是针刺TGN领域体表穴位调控孤束核内脏机能的结构基础。

The indirect pathway of the somatic afferent elements from trigeminal nerve (TGN) to nucleus tractus solitarii (NTS) was studied with the light and electron microscopic HRP transganglionic and retrograde tracing. After HRP was injected into NTS at the level of obex, the retrogradely labeled cells were mainly found in the interstitial nucleus buried in the spinal tract of TGN along caudal subnucleus. The interstitial nucleus was also the terminating area of the primary afferent fibers of lingual and inferior orbital nerves. Under electron microscope, it was found that the primary afferent terminals of lingual and inferior orbital nerves formed synapses on the dendrites of neurons in the interstitial nucleus. Moreover, in cellular architecture, the interstitial nucleus and the superficial laminae of the caudal nucleus of TGN were similar and continuous with each other. Hence, the pathway from the TGN to NTS via the interstitial nucleus is consisted of two neurons and the sensations transmitted through this pathway may be considered to be somatic. It is presumed that this pathway composed of two neurons might modulate the visceral afferent function in NTS when certain points in the skin area innervated by TGN were acupunctured.