面口部三叉神经躯体性初级传入和内脏性初级传入在三叉神经脊束间质核汇聚的电镜研究

本教研室既往研究曾发现三叉神经脊束间质核不仅接受支配面、口部皮肤和粘膜的下牙槽神经、舌神经和眶下神经等三叉神经范围的初级传入 ,还接受舌咽、迷走神经的内脏初级传入。继之又证明 ,投射于三叉神经脊束间质核的舌神经、眶下神经和舌咽、迷走神经的初级传入终末都主要分布在相当于闩水平的三叉神经脊束间质核的梭形、柱状膨大部分 ,且两者的终末分布区存在着明显的重叠。因此设想 ,此两种传入终末可能汇聚于三叉神经脊束间质核内的神经元并与之形成突触联系。为了证实此点 ,本研究将 HRP和神经毒 ricin分别注入于舌咽、迷走神经和眶下神经 ,在电镜下对它们的终末分布状态和联系进行了探索。发现有多数的此两类终末与树突分别构成突触连结 ;还发现一些标记的和溃变的终末共同汇聚于同一间质核神经元 ,其数量分别占标记终末总数的 1.43%和变性终末总数的 6 .5 7%。本文首次在形态学上证明直接来自三叉神经躯体性和来自 、 脑神经内脏性初级传入终末汇聚于间质核神经元形成双重突触连结。推论 ,来源不同的外周躯体性和内脏性传入信息可能藉此汇聚而互相作用实现功能上的整合

THE ELECTRON MICROSCOPIC STUDY OF CONVERGENCE OF THE PRIMARY AFFERENT TERMINALS FROM THE TRIGEMINAL NERVE INNERVATING OROFACIAL REGION AND VISCERAL NERVES IN THE INTERSTITIAL NUCLEUS OF THE SPINAL TRIGEMINAL TRACT

The interstitial nucleus of the trigeminal spinal tract(INV) consists of the clusters of neurons locating in and near the dorsal part of the trigeminal spinal tract. INV not only receives the primary afferent terminals from lingual, inferior alveolar and inferior orbital nerves innervating the skin and mucosa of the orofacial regions, but also the visceral afferent terminals from the glossopharyngo-vagal nerves innervating the digestive tract, larynx and pharynx. By using the methods of transganglionic labeling of HRP and reconstructing by computer-aided image analysis, it was further demonstrated that distribution of the primary afferent terminals from the lingual, inferior orbital, glossopharyngeal and vagus nerves were obviously overlapping with each other in the enlarged regions of the fusiform column of the INV at the level of the obex. There may be convergent among those primary afferent terminals. After injecting HRP and ricin into the glossopharyngo-vagal and inferior orbital nerves, respectively, under electron microscope, many labeled and degenerated fibers and terminals were found in the INV. Although the majority of those two kinds of terminals contacted with dendrites, respectively, some labeled and degenerated terminals made synapses with the same dendrites, and their population were 1.43% and 6.75%, respectively,in the total numbers of labeled and degenerated terminals observed. It is suggested that, the results of the present study might prove morphologically that the primary afferent terminals of somatic and visceral nerves converged and made double synapses with intermediate neurons in INV. The convergence of different inputs may interact with each other and modulate somato-visceral reflex, including the significant afferent nociceptive information.