SYNAPSE FORMATION AND GROWTH IN AN AUTONOMIC GANGLION

自主神经节中突触的形成和生长

• 批准号: 3408434
• 负责人: PETER B. SARGENT
• 金额: $ 5.07万
• 依托单位: UNIVERSITY OF CALIFORNIA RIVERSIDE
• 依托单位国家: 美国
• 财政年份: 1986
• 资助国家: 美国
• 起止时间: 1986-03-01 至 1989-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3408434
• 关键词: acetylcholinesterase; autonomic ganglion; cell growth regulation; innervation; larva; mature animal; metamorphosis; neural information processing; neuroanatomy; neurophysiology; synapses; tissue mosaicism

The long-range objective of my research is to understand the mechanisms that underlie the formation of synapses between neurons during embryogenesis. The specific objectives of this proposal are 1) to complete an analysis of synaptic growth in the cardiac ganglion of postmetamorphic Xenopus laevis and 2) to study the initial formation and the growth of synapses on developing cardiac ganglion cells in larval animals. In mature animals the innervation of individual neurons is dominated by a preganglionic axon which supplies all the synaptic boutons found on the ganglion cell body. During postmetamorphic life the total area of synaptic contact grows by an increase in bouton number, and the increase in bouton number is exactly matched by an increase in ganglion cell size. By studying transmitter release from the principal synaptic input to ganglion cells and by counting boutons on physiologically characterized cells, we shall determine whether boutons represent equivalent amounts of transmitter release and whether they represent the functional unit of synaptic growth. By studying the innervation of both diploid and larger tetraploid ganglion cells in chimeric animals, we hope to determine the basis of the compensatory growth of cell size and bouton number in postmetamorphic animals. The arrival of preganglionic axons in the developing cardiac ganglion will be visualized by filling techniques, and nascent synapses will be studied both anatomically and physiologically. How do the structure and release properties of newly formed boutons compare with those of mature ones? The growth of synapses in larval animals will be analyzed to learn whether boutons are the units of synaptic growth from the very onset of synaptogenesis. Synapse elimination will be investigated by physiological techniques, and we shall ask whether the ganglion cell body is ever innervated by more than one preganglionic axon. Finally, we shall search for transient connections between ganglion cells. Such connections are ordinarily suppressed by preganglionic innervation but may appear early in development. These studies will increase our understanding of how synapses between neurons form and grow during development. They will also identify the stages when the process of synapse formation may go awry.

我研究的长期目标是了解其机制 是神经元之间突触形成的基础 胚胎发生。 本提案的具体目标是 1) 完成 变态后心神经节突触生长的分析 非洲爪蟾 (Xenopus laevis) 和 2) 研究其初始形成和生长 突触对幼虫动物心脏神经节细胞发育的影响。 成熟时 动物个体神经元的神经支配是由 节前轴突，提供所有在神经节上发现的突触纽扣 神经节细胞体。 在变态后的生活中，突触的总面积 联系随着 bouton 数量的增加而增长，并且 bouton 的增加 数量与神经节细胞大小的增加完全匹配。 经过 研究神经节主要突触输入的递质释放 细胞并通过对具有生理特征的细胞进行计数，我们 应确定 boutons 是否代表等量的发射器 释放以及它们是否代表突触生长的功能单位。 通过研究二倍体和较大的四倍体神经节的神经支配 嵌合动物细胞中，我们希望确定其基础 变态后细胞大小和布顿数的补偿性增长 动物。 节前轴突到达发育中的心脏神经节将 通过填充技术可视化，并将研究新生突触 解剖学和生理学上。 如何构建和发布 新形成的纽扣与成熟的纽扣相比有何特性？ 这 将分析幼虫动物突触的生长，以了解是否 boutons是突触从一开始就生长的单位 突触发生。 将通过生理学研究突触消除 技术，我们要问神经节细胞体是否曾经 受多个节前轴突支配。 最后我们要搜索 用于神经节细胞之间的瞬时连接。 此类连接是 通常受到节前神经支配的抑制，但也可能出现在节前神经支配的早期 发展。 这些研究将增加我们对突触之间如何相互作用的理解。 神经元在发育过程中形成和生长。 他们还将确定 突触形成过程可能出错的阶段。