中华宽体金线蛭神经元形态的相似性及对称性

本文用细胞内注射辣根过氧化物酶的方法研究了中华宽体金线蛭体神经节内几种不同机能的标定神经元轴突分枝形态。对每一种神经元分别进行比较,确定其代表型。结果证明:标定神经元轴突分枝的形态在个体内和个体间具有精确的相似性;同一神经节内两侧的标定神经元轴突分枝具有稳定的对称性。对这种对称神经系统形成的可能原因及其机能意义进行了讨论。     

INTERNALIZATION OF GAP JUNCTIONS BETWEEN NEURON AND GLIAL CELL AND FORMATION OF ANNULAR LAMELLAR BODIES IN CHINESE LEECH Whitmania pigra

This paper reveals the formation of annular lamellar body (ALB) in the ganglion of leech by means of in situ fixation and the lanthanum nitrate tracer technique. This formation involves both wrapping and internalization of the gap junctions between glial processes themselves, as well as between neuron and glial process. The results indicate that there is probably an active process of internalization of membrane structures involving gap junctions between neuron and glial cell in the central nervous system in leech. The functions of ALB are discussed.     

THE MORPHOLOGICAL SIMILARITY AND SYMMETRY OF NEURONES IN THE LEECH Whitmania pigra

Using the method of intracellular injection of horseradish peroxidase, the arborizations of several neurones with different functions in the segmental ganglia of the leech Whitmania pigra are investigated. Comparison is made in each kind of neurones in order to verify their typical pattern. Results show that the morphology of the axonal arbors of identified neurones has an accurate similarity within and among the individuals of the leech, and the axonal arborizations of the bilaterally identified neurones in the same ganglion have a stable symmetry. The possible reasons of the formation and its functional significance of the symmetrical nervous system are discussed.     

Orientational Recognition and Low-Resistance Passing (LRP) Regulation of Segmental Re-innervation by Central Neurons in Leeches

Re-innervation of sensory and motor neurons on a defined area of the body wall was studied in two species of leeches, Whitmania pigra and Hirudo medicinalis, as a model of segmental animals. Following isolation and rotation of a tube of body wall, the mechanical sensory and annular erection (AE) motor neurons re-innervated the body wall, at a rate of approximately 3. 8 -8. 4 μm/h. The patterns of re-innerva-tion by pairs of neurons on each side of a ganglion were bilaterally symmetric. The repairs are synchronous for the sensory and motor neurons which are of different functions but in a same ganglion. The gap junctions are widely spread in leech between neurons and glia cells, as well as among the neurons and glia cells themselves. Therefore, it is proposed that the nervous system repair is regulated by a low-resistance pathway. In the xenotransplantation experiments, neurons recognized target tissues before the immuno-recognition and rejection.     

单个含5-HT神经元植入水蛭离体神经节后突触联结的再发生

单个含5-HT的成熟Retzius细胞被植入正常离体神经节中进行培养,用细胞内微电极检测植入Retzius细胞的性质,以及它与神经节中原有标定神经细胞的联结。在培养第3天时,植入的Retzius细胞保持正常水平膜电学性质;并与神经节中的Retzius细胞形成了非整流电学耦联,与L运动神经元间形成了整流性电学耦联;此外,植入Retzius细胞接受来自神经节中伤害性和触觉感受神经元冲动的化学性传入,植入Retzius细胞的冲动并可诱发L运动神经元中突触电位。本文报道植入额外的成熟神经元可形成新生突触联结,并论述它可能重现中枢神经系统的早期功能发生。     

水蛭中枢神经元节段再支配的方位识别与低阻贯通调节

本文以中华宽体金线蛭和欧洲医蛭作为体节动物模型,研究感觉与运动神经元再支配体表确定区如何识别方位。当一段游离体壁管被旋转后,机械性感受细胞与耸环运动细胞以3.8—8.4μm/h修复再支配区。神经节双侧成对同名神经元对称修复;感觉与运动不同功能神经元同步修复。水蛭的神经元与胶质细胞各自及相互间均有缝隙连接,故提出由低阻贯通方式调节神经系统修复。对异种移植体壁再支配实验中神经元末梢对靶识别与连接先于免疫识别与排斥出现。     

RE-DEVELOPMENT OF SYNAPTIC CONNECTIONS AFTER IMPLANTED SINGLE 5-HT CONTAINING NEURON IN ISOLATED LEECH GANGLIA

Single mature Retzius cells which contain 5-HT have been implanted in isolated ganglia of Whitmania pigra. The properties of the implanted Retzius cell and its connections with the original identified nerve cells of the ganglia have been measured by intracellular microelectrodes. At 3 days in culture an implanted Retzius cell maintains its normal electrical membrane properties. It also forms the non-rectifying electronic coupling with the original Retzius cell and rectifying junctions with the L motor neuron of the host ganglion. In addition it receives chemical inputs of the impulse from T and N sensory neurons of ganglion. Impulses in the implanted Retzius cell evoke synaptic potentials in the L motor neuron, In this paper the appearance of novel synapses, which are formed by implanting an extra mature neuron as a pre- or post-synaptic element, is described. It might represent functional development of central nervous system at an earlier stage.     

中华宽体金线蛭神经元-胶质细胞间隙连接内部化形成环形片层体

本文以水蛭神经节为材料,活体原位固定并以镧离子示踪,详细显示了神经元与胶质细胞突起之间,胶质细胞突起自身之间的间隙连接,及其旋卷并不断内部化而形成环形片层体的过程。由此揭示中枢神经系统中神经元与胶质细胞间可能存在活跃地形成间隙连接并内部化的过程,以及间隙连接的膜结构在这两种细胞中的兼容现象。讨论了环形片层体的机能意义。