大鼠腰后段背根节神经元周围突的分支分布——荧光素双标记法研究

DISTRIBUTION OF THE DICHOTOMIZING BRANCHES OF PERIPHERAL PROCESSES OF CAUDAL LUMBAR DORSAL ROOT GANGLION NEURONS IN THE RAT——A DOUBLE FLUORESCENCE LABELLING STUDY

本研究应用2组荧光素配伍(FB-NY,PI-Bb)的双标记技术,进行了下列3组实验:1.将各配伍组的2种荧光素分别注入大鼠一侧胫神经干和腓神经干;2.分别注入一侧的腓肠皮神经和小腿三头肌神经:3.分别注入胫神经和同侧膀胱壁内。前两组在注入侧 L_(4～8)背根节内用荧光显微镜观察到的标记细胞中约12%为双标记细胞;而第3组仅在注入侧 L_6背根节中见到少量双标记细胞。双标记细胞的大多数为小型(33.1%)和中小型(40.9%)细胞。本文结果表明:背根节细胞周围突有相当一部分是分叉的,它们的2个分支或分布于2条躯体神经,或分别分布于皮肤和肌肉,甚至可分别分布于躯体和内脏的不同感受野。这一结果为阐明牵涉痛和针刺对内脏活动调控的神经机制,提供了一定的形态学基础。

The technique of double labelling with fluorescent tracers(FB-NY,PI-Bb)has. been used in the following three groups of experiments:1.in 5 rats,one fluorescent tracer was injected into the tibial nerve and the other was injected into the peroneal nerve;2.in 14 rats,one fluorescent tracer was injected into the sural cutaneous nerve and the other was injected into the branches to the soleus and gastrocnemius muscles;3.in 13 rats,one tracer was injected into the tibial nerve and the other into the bladder wall.The sections of the L_(3-6),S_(1-3) dorsal root ganglion were stu- died with a olympus fluorescence microscope using UG-1 excitation filter system. In the first and second groups,double labelled neurons were observed in L_(4-6) dorsal root ganglion.But in the third group,the double labelled neurons were found only in the L_6 segment.The type of the double labelled neurons was mainly small-sized (33.1%)and small-medium sized(40.9%). The findings indicated that,the primary afferent fibers branched towards the periphery and supplied,with different branches,either two somatic areas or skin and deep structures,or,especially,visceral and somatic sensory fields.This result suggests that the peripheral dichotomization of these dorsal root ganglion cells might converge sensory inputs from the somatic(tibial nerve)and the visceral(bladder wall)fields and thus provides one of the structural basis for the referred pain and the neuronal mechanism of acupunctural therapy by which stimulation of somatic structures could regulate the activities of visceral organs.