功能确定后的HRP细胞内注射标记的三叉神经中脑核神经元的电镜研究

在猫的Ｐｒｏｂｓｔ束纤维内记录并注射ＨＲＰ，确定出支配咬肌肌梭的三叉神经中脑核神经元，对其进行了连续切片电镜观察．发现约有１０个不明来源的终扣与被标记的中脑核神经元密切接触，其中４个与之形成明确的突触．突触有两种类型：对称性含混合透明小泡（圆形、椭圆形和扁平小泡）者和非对称性含圆形透明小泡者．另外后者也含有为数很少、散在分布的小圆形致密芯颗粒小泡．在其它与标记胞体密切接触的终扣内，也可见到不规则分布的致密芯颗粒小泡．本文对上述所见的可能的功能机制进行了讨论。

ELECTRON MICROSCOPIC STUDY ON THE FUNCTIONALLY IDENTIFIED AND INTRACELLULARLY LABELED MESENCEPHALIC TRIGEMINAL NEURON IN CAT

Intra-axonal recording and babelling with HRP were performed to examine Synaptic contacts of mesencephalic trigeminal sinrons(Vme) innervating the masseter muscle-spindles. Intra-axonal injection of HRP was made in the mesencephalic tract. A single spindle afferent was intracellularly labeled with HRP and then was processed and oborved under electron microscope. About ten boutons contacting a labeled soma, were obserVed from serial uhrathin sections; Among them four boutons synapeed on the labeled soma, and they could be identified as symmetrical or asymmettical type. The teutons forming symmetryal synapses pretained pleomorphic clear vesicles (a mixture of round, oval and nattened). Those forming asymmetrical synapses contained predominantly spherical clear vesicles with occational dense-core veaicles. The dense-core granular vesicles were also randomly scattered in the other terminals contacting the labeled soma. The possible function of these observations has ben discussed in the present study.