三叉神经本体觉中枢通路第二、三级神经元之间突触连接的发现及突触构筑学研究—溃变与HRP逆行追踪法相结合的电镜观察

将HRP注入丘脑腹后内侧核逆行追踪,将海人酸注入三叉神经脊束核吻侧亚核背内侧部造成顺行溃变,在电镜下对王百忍等发现的三叉神经本体觉中枢通路三级神经元所在地—”带状区”内的二、三级神经元的突触联系进行了探索。结果在“带状区”内发现了由溃变终末与HRP逆行标记的胞体、树突形成的轴-体、轴-树突触,从而在突触水平确证了这条通路的存在。另外还发现,同时存在着由正常轴突终末与HRP逆标神经元胞体、树突所形成的轴-体或轴-树突触;正常轴突终末与溃变终末所形成的轴-轴突触;溃变终末与未标记的神经元胞体、树突所形成的轴-体、轴-树突触。还见到少量的突触小球结构。本文也对”带状区”突触连接模式的特征及意义作了讨论。

SYNAPTIC CONNECTIONS BETWEEN SECOND-ORDER AND THIRD-ORDER NEURONS IN THE TRIGEMINAL PROPRIOCEPTIVE PATHWAY-AN ULTRASTRUCTURAL STUDY USING COMBINED HRP RETROGRADELY LABELLING AND KAINIC ACID DEGENERATION TECHNIQUE IN THE RAT

After kainic acid was injected into the dorsomedial part of the subnucleus oralis (Vodm) to induce degeneration of the 2nd order neuron, HRP was introduced into the ventral posteriomedial nucleus of the contralateral thalamus to label the 3rdorder neuron retrogradely. The synaptie connections between second order and third order neurons were examined by electron microscopy in the "Zone-area", namely the ADO. AVM and gpdm, which was previously reported by Wang and Li. From the results of the present study, the degenerated terminals were found to make synaptic contacts with HRP retrogradely labelled somata or dendrites. Therefore, the trigeminal proprioceptire pathway proposed by Wang and Li has been demonstrated at ultrastrueture level. Ultrastructural characteristics of the "Zone-area" were also studied, axo-somatic or axo-dendritic synapses between normal terminal and HRP retrogradely labelled neuron were seen: axo-axonic synapses between normal and degenerated terminals were also observed; simple contacts were present between the degenereted endings and unlabelled somata or dendrites in these regions. Some synaptic glomeruli were also found in the areas. The significance of these findings and characteristic of the synaptic cotmectifons were dis cussed.