Light Adaptation in Cone Photoreceptors

描述（申请人提供）：视锥细胞调节日常视觉，视锥细胞如何适应明亮的照明是其功能的内在组成部分。尽管它们对视觉很重要，但人们对视锥细胞如何适应光线知之甚少。本研究旨在阐明视锥细胞光适应的分子机制，并分析这些机制如何影响视锥细胞在强光下的功能和性能。第一个具体目标是确定视锥细胞对长时间背景光的反应，关注循环电流对稳定照明的缓慢变化。第二个具体目标是通过研究微光响应动力学来确定光转导级联的增益和速度在背景光下的变化。第三个具体目标是测量光转导级联的特定成分对适应的敏感性和贡献。这些实验测试了适应过程中特定机制如何调节光转导级联的增益和速度。整个过程中使用了吸电极技术，允许从单个完整的光感受器进行记录。

DESCRIPTION (provided by applicant): Cones mediate everyday vision, and how cones adapt to bright illumination is an intrinsic part of their function. Despite their importance to vision, little is known about how cones adapt to light. The research proposed here aims to elucidate the molecular mechanisms of light adaptation in cones, and dissect how these mechanisms impact the function and performance of the cone in bright light. The first specific aim determines how cones respond to prolonged background light, focusing on slow changes in circulating current in response to steady illumination. The second specific aim determines how the gain and speed of the photo transduction cascade changes under background light by studying the kinetics of the dim flash response. The third specific aim measures the sensitivity and contribution of specific components of the photo transduction cascade to adaptation. These experiments test how specific mechanisms regulate the gain and speed of the photo transduction cascade during adaptation. A suction electrode technique is used throughout, which allows recording from individual, intact photoreceptors.