Dynamic modulation of retinal ribbon-type synapses

视网膜带状突触的动态调制

• 批准号: 8632259
• 负责人: HENRIQUE Prado VON GERSDORFF
• 金额: $ 38.5万
• 依托单位: OREGON HEALTH & SCIENCE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-05-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8632259
• 关键词: Adult; Amacrine Cells; American; Applications Grants; Biological Assay; Blindness; Buffers; Calcium; Cells; Cone; Coupling; Cyclic AMP; Data; Detection; Development; Devices; Docking; Egtazic Acid; Electric Capacitance; Electrophysiology (science); Exocytosis; Eye; Funding; Future; Glutamates; Glycine; Image; Impairment; In Situ; Inhibitory Synapse; Interneurons; Kinetics; Knowledge; Lead; Life; Light; Macular degeneration; Measurement; Measures; Membrane; Mental Depression; Monitor; Mus; Neurons; Neurotransmitters; Output; Pattern; Photoreceptors; Physiologic pulse; Physiological; Plastics; Probability; Property; Prosthesis; Recovery; Recruitment Activity; Recycling; Retina; Retinal; Retinal Diseases; Retinitis Pigmentosa; Series; Slice; Stimulus; Synapses; Synaptic Transmission; Synaptic Vesicles; Synaptic plasticity; Techniques; Testing; Time; Vesicle; Vision; Vision Disorders; Visually Impaired Persons; Work; controlled release; design; ganglion cell; insight; patch clamp; postnatal; postsynaptic; presynaptic; public health relevance; research study; response; retinal prosthesis; sensor; synaptic depression; time use; voltage clamp

PROJECT SUMMARY Bipolar cell and amacrine cell synapses are key components of the vertebrate retinal circuitry with multiple specialized functions. The underlying cellular mechanisms that control transmitter output from the ribbon-type synapses of bipolar cells and the conventional inhibitory synapses of amacrine cells, under vastly different ambient light conditions, are still poorly understood in the mammalian retina. Here we propose to do a series of patch-clamp electrophysiology and calcium imaging experiments on single amacrine cells of the mouse retina. This allows us to measure both presynaptic Ca2+ currents and evoked changes in membrane capacitance that assay synaptic vesicle exocytosis in real time from a living cell. We will apply calcium imaging and membrane capacitance techniques to the AII amacrine cell, a major interneuron in the mammalian retina that releases glycine at conventional active zones that contain a large cluster of synaptic vesicles. We will determine the overall capacity for exocytosis of a single AII amacrine cell. We will test the hypothesis that AII amacrine cells contain three distinct readily releasable pools of vesicles that have different sizes and kinetics of exocytosis. The mechanisms that maintain and modulate glycine release and short-term plasticity from AII amacrine cells are not known. We will test the hypothesis that cAMP levels modulate the kinetics of glycine release, the size of the readily releasable vesicle pool, and the short-term plasticity at AII amacrine cell synapses. We will also perform these measurements on AII amacrine cells during early postnatal development. We will test the hypothesis that the coupling between vesicles and the Ca2+ sensor for exocytosis becomes tighter during early development as Ca2+ currents increase in size and as Ca2+ channels become more colocalized with docked vesicles at the active zones of AII amacrine cells. Finally, using a combination of voltage-clamp and current- clamp recordings we will measure the degree of exocytosis from single AII amacrine cells that is evoked by physiological stimuli, namely, light stimuli of different intensities. In summary, the results of this grant proposal will provide a better understanding of how AII amacrine cells modulate bipolar cell terminal release via dynamic and plastic inhibitory synapses.

项目摘要 双极细胞和无长突细胞突触是脊椎动物视网膜回路的关键组成部分， 专门功能。控制带状神经元传导输出的基本细胞机制 双极细胞的突触和无长突细胞的传统抑制性突触，在巨大不同的条件下， 在哺乳动物视网膜中，环境光条件仍然知之甚少。在这里，我们建议做一系列的 小鼠视网膜单个无长突细胞的膜片钳电生理和钙成像实验。 这使我们能够测量突触前Ca2+电流和诱发的膜电容变化， 测定活细胞中真实的突触囊泡胞吐作用。我们将应用钙成像和膜 AII无长突细胞是哺乳动物视网膜中的主要中间神经元， 甘氨酸在常规的活性区，包含一个大簇的突触囊泡。康贝特人将以 单个AII无长突细胞胞吐的总能力。我们将检验所有无长突细胞 含有三种不同的容易释放的囊泡池，其具有不同的大小和胞吐动力学。 维持和调节AII无长突细胞甘氨酸释放和短期可塑性的机制 不知道。我们将检验cAMP水平调节甘氨酸释放动力学的假设， 的易释放囊泡池，并在AII无长突细胞突触的短期可塑性。我们还将 在出生后早期发育期间对AII无长突细胞进行这些测量。我们将测试 假设囊泡和胞吐的Ca2+传感器之间的耦合在早期变得更紧密， 随着Ca 2+电流大小的增加以及Ca 2+通道与对接变得更加共定位，发展 AII无长突细胞活动区的囊泡。最后，使用电压钳位和电流钳位的组合， 我们将测量单个AII无长突细胞的胞吐作用的程度， 生理刺激，即不同强度的光刺激。总而言之，这项拨款申请的结果 将提供一个更好的理解如何AII无长突细胞调节双极细胞终末释放， 动态和可塑性抑制性突触。