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 双极细胞和无链氨酸细胞突触是脊椎动物视网膜电路的关键组成部分， 专业功能。从色带类型控制发射机输出的基础细胞机制 双极细胞的突触和无链氨酸细胞的常规抑制突触，在截然不同的下 在哺乳动物的视网膜中，环境光条件仍然很少了解。在这里，我们建议做一系列 小鼠视网膜的单个无链氨酸细胞上的贴片钳电生理学和钙成像实验。 这使我们能够测量突触前Ca2+电流和诱发膜电容的变化， 实时从活细胞实时实时测定突触囊泡胞吐作用。我们将应用钙成像和膜 AII amacrine细胞的电容技术，哺乳动物视网膜中的主要神经元释放 甘氨酸在传统的活性区域，其中包含大量突触囊泡。我们将确定 单个AII裁活细胞胞吐作用的总体能力。我们将测试AII临床细胞的假设 包含三个不同易于释放的囊泡池，这些囊泡具有不同的大小和动力学的胞吞作用。 维持和调节甘氨酸释放和从AII无小细胞的短期可塑性的机制 不知道。我们将检验以下假设：cAMP水平调节甘氨酸释放的动力学，大小 易于释放的囊泡池和AII无链氨氨酸细胞突触的短期可塑性。我们也会 在产后早期发育期间，对AII无大细胞进行了这些测量。我们将测试 假设囊泡与Ca2+传感器之间的胞吞作用之间的耦合在早期变得更紧 随着Ca2+电流的大小增加，随着Ca2+通道的增加，发展 AII无链氨酸细胞的活性区域的囊泡。最后，使用电压夹和电流的组合 夹具记录我们将测量单个AII无链氨酸细胞的胞吐作用程度 生理刺激，即不同强度的光刺激。总而言之，该赠款提案的结果 将更好地理解AII无链氨酸细胞如何通过 动态和塑性抑制突触。