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Transmitter substances of retinal neurons

视网膜神经元的递质物质

基本信息

批准号：
61440026
负责人：
KANEKO Akimichi
金额：
$ 6.72万
依托单位：
Okazaki National Research Institute
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (A)
财政年份：
1986
资助国家：
日本
起止时间：
1986 至 1988
项目状态：
已结题

项目摘要

Knowledge on the synapic transmission is essential for the understanding of a nervous system. The aim of the present study was to understand the action of synaptic transmitter in the vertebrate retina. We recorded membrane currents of solitary neurons by using patch clamp technique in the whole cell configuration. Cells were dissociated from the retina of goldfish, turtle and mouse. The following is a list of major findings.1. Uptake of L-glutamate by photoreceptors. It is now generally accepted that L-glutamate is released from photoreceptors. L-Glutamate is taken up by photoreceptors by a transport system. Electrochemical gradient of Na^+ is the enegy source for transport; 3 Na^+ are co-transported with each glutamate modecule. Thus, this system is electrogenic, causing depolarization in all subtypes of photoreceptors. It is likely that this mechanism contribute in excitatory interaction among heterologous photoreceptors.2 Inhibition mediated by -aminobutyric acid (GABA) from amacrin … More e cell to bipolar cell. GABA induced hyper-polarization in goldfish bipolar cells by opening chloride channels mediated by GABAalpha receptor.3. Transient calcium current of mouse bipolar cells. Calcium current (I_<ca>) in mouse bipolar cells is T-type showing rapid inactivation. I_<ca> flowed through the axon terminal as well as the soma. It is hypothesized that the transmitter release from bipolar cell terminal is also transient. Thus, I_<ca> of mouse bipolar cells may contribute in shaping transient light evoked responses in amacrine and ganglion cells.4. Connectivity between photoreceptors and horizontal cells in the turtle retina. Subtypes of turtle cones are readily identified morphologically by their colored oil droplets. Using this index, we analyzed connectivity of photoreceptors and horizontal cells. Contrary to the general belief, red-sensitive cones were found to make direct connection to H_2 and H_3 horizontal cells. Color vision models are discussed based on this new finding. Less

了解突触传递对于了解神经系统是必不可少的。本研究的目的是了解突触递质在脊椎动物视网膜中的作用。采用膜片钳技术在全细胞构型下记录单个神经元的膜电流。从金鱼、乌龟和小鼠的视网膜中分离细胞。以下是主要调查结果的清单。光感受器摄取L-谷氨酸。现在普遍认为L-谷氨酸是从光感受器释放的。L-谷氨酸通过转运系统被光感受器吸收。Na^+的电化学梯度是转运的能量来源; 3 Na^+与每个谷氨酸模块共转运。因此，该系统是产电的，引起所有光感受器亚型的去极化。这种机制可能有助于异源光感受器之间的兴奋性相互作用。2由来自amacrin的-氨基丁酸（GABA）介导的抑制 ...更多信息 e细胞到双极细胞。GABA通过开放GABA α受体介导的氯离子通道诱导金鱼双极细胞超极化.小鼠双极细胞的瞬时钙电流。小鼠双极细胞的钙电流（I_<ca>）为T型，表现为快速失活。I_<ca>流经轴突终末和索马。假设双极细胞终末的递质释放也是短暂的。因此，<ca>小鼠双极细胞的I_2可能参与了无长突细胞和神经节细胞的瞬态光诱发反应的形成.海龟视网膜中光感受器和水平细胞之间的连接。龟锥的亚型很容易通过它们的彩色油滴在形态上识别。使用该指数，我们分析了光感受器和水平细胞的连接性。红敏视锥与H_2和H_3水平细胞有直接联系。基于这一新的发现，颜色视觉模型进行了讨论。少