DEVELOPMENT OF SYNAPSES BETWEEN IDENTIFIED NEURONS

已识别神经元之间突触的发育

• 批准号: 6496791
• 负责人: JONATHAN M BLAGBURN
• 金额: $ 24.35万
• 依托单位: UNIVERSITY OF PUERTO RICO MED SCIENCES
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-05-01 至 2002-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6496791
• 关键词: action potentials; afferent nerve; axon; cockroach; developmental neurobiology; electron microscopy; electrophysiology; embryogenesis; ganglions; histochemistry /cytochemistry; interneurons; light microscopy; mathematical model; mutant; nervous system regeneration; neuroanatomy; neuronal guidance; statistics /biometry; synapses; synaptogenesis

The functioning of the nervous system is dependent on the accurate establishment of synaptic circuits. The long-term goal of this work is to understand the mechanisms by which specific synaptic connections are formed, and the ways that these connections are adjusted during development. These questions are being addressed using a well-defined population of sensory neurons and interneurons in the cercal system of cockroach Periplaneta americana. The specific aims of this proposal are described below: There is a 20-fold increase in sensory input during the transition from first to second stage larva, a period of only 8 days. Our first aim is to determine the times of birth, axonal ingrowth and synapse formation of the new sensory neurons, an essential prerequisite for the later experiments. The second aim is to test the hypothesis that the Engrailed protein forms part of a system of positional information which determines the axon anatomy and synaptic connectivity of sensory neurons. The effects of antisense oligonucleotides and misexpression of Enrailed on the axonal arborizations and synaptic connections of developing sensory neurons will be assessed, using intracellular dye injection, electron microscopy and electrophysiology. The third aim is to test the role of cyclic AMP-dependent protein kinase (PKA), an antagonist of the Hedgehog signaling pathway, in determining axon arborization and synaptic connectivity. PKA will be activated or inhibited pharmacologically. The fourth aim is to investigate how the strengths of sensory neuron to interneuron synapses are adjusted as the animal grows and new inputs enter the nervous system. The experimental approaches include intracellular recording, quantal analysis, intracellular dye injection, and morphometric analysis. Many of the basic mechanisms which control the formation of neural circuitry appear to have been conserved during evolution, so the results derived from this study should be relevant to synapse formation during the development and regeneration of the human nervous system.

神经系统的功能依赖于突触回路的准确建立。 这项工作的长期目标是了解特定突触连接形成的机制，以及这些连接在发育过程中调整的方式。 这些问题正在解决使用一个定义明确的人口的感觉神经元和interneurons在cercal系统的蟑螂美洲大蠊。 这项建议的具体目标如下：在从第一阶段到第二阶段幼虫的过渡期间，感觉输入增加了20倍，只有8天的时间。 我们的第一个目标是确定新感觉神经元的出生时间、轴突长入和突触形成，这是以后实验的必要先决条件。第二个目的是检验Engrailed蛋白形成位置信息系统的一部分的假设，该位置信息系统决定感觉神经元的轴突解剖和突触连接。 将使用细胞内染料注射、电子显微镜和电生理学评估反义寡核苷酸和Enrailed的错误表达对发育中的感觉神经元的轴突分支和突触连接的影响。 第三个目的是测试环腺苷酸依赖性蛋白激酶（PKA），刺猬信号通路的拮抗剂，在确定轴突分支和突触连接的作用。 PKA会被激活或抑制。 第四个目的是研究感觉神经元与中间神经元突触的强度如何随着动物的生长和新的输入进入神经系统而调整。 实验方法包括细胞内记录、量子分析、细胞内染料注射和形态计量学分析。许多控制神经回路形成的基本机制似乎在进化过程中得到了保护，因此这项研究的结果应该与人类神经系统发育和再生过程中的突触形成有关。