SYNAPTIC MECHANISMS IN THE VERTEBRATE RETINA

抑制性氨基酸在脊椎动物中扮演着多种角色 视网膜。直到最近，人们还认为这些病毒的唯一作用是 递质是对氯离子门控通道的直接作用。现在是时候了 很明显，GABA和甘氨酸调节其他通道，通过 第二信使，并调节其他受体，如NMDA型 谷氨酸受体。基于这些新的发现，这项提案提供了 为了重新检查抑制性氨基酸的作用，集中在 伽玛能系统。其中一个目标是更多地了解GABAB 受体系统。一个特定的目标是确定 GABAB受体存在于视网膜中，描述它们的电导 机理及其对电压和光相关特性的影响 视网膜神经元。GABAB受体对特异体表型的影响 信息通路，尤其是对抗性环绕反应 远端视网膜和近端视网膜的方位敏感性， 将会被调查。另一个目标是映射本地化的 氨基丁酸和甘氨酸在无长突和无长突树突上的应用 神经节细胞。一个具体的目标是检验GABAA和GABAA的假设 甘氨酸在胞体附近时会产生超极化 当应用于树突的远端部分时，去极化 检测GABAB受体是否集中在远端 树枝状结构。GABA和GABA之间似乎也存在相互作用 视网膜中的甘氨酸受体，这可能代表着 配体作用，一种受体亚型，对GABA和 甘氨酸，或异源脱敏。该机制和 这种相互作用的意义将被研究。此外， GABAc受体Will在视网膜中的可能意义 被探索。总体而言，这项研究将试图提供一种 了解GABA受体亚型在视网膜中的作用 突触机制和信息处理。

Inhibitory amino acids play a multiplicity of roles in the vertebrate retina. Until recently it was thought that the sole effect of these transmitters was a direct action on chloride gated channels. It is now evident that GABA and glycine regulate other channels, act through second messengers, and modulate other receptors such as the NMDA-type glutamate receptor. Based on these new findings, this proposal offers to re-examine the actions of inhibitory amino acids, concentrating on the GABAergic system. One goal is to learn more about the GABAb receptor system. A specific aim is to determine if subtypes of the GABAb receptor are present in the retina, describe their conductance mechanisms, and their effects on voltage and light dependent properties of retinal neurons. The effect of GABAb receptors on specific information pathways, particularly the antagonistic surround response in the distal retina and orientation sensitivity in the proximal retina, will be investigated. Another goal is to map the effect of localized applications of GABA and glycine along the dendrites of amacrine and ganglion cells. A specific aim is to test the hypotheses that GABAa and glycine produce hyperpolarizations when applied near the soma but depolarizations when applied to distal portions of dendrites, and to test whether GABAb receptors are concentrated at the distal ends of dendrites. There also appears to be an interaction between GABA and glycine receptors in the retina, which may represent a crossover in ligand action, a receptor subtype that is sensitive to both GABA and glycine, or heterologous desensitization. The mechanism and significance of this interaction will be studied. In addition, the possible significance in the retina of the putative GABAc receptor will be explored. Overall, this research will attempt to provide an understanding of the roles GABA receptor subtypes play in retinal synaptic mechanisms and information processing.