PHOTORECEPTION AND TRANSDUCTION IN VISION

描述(改编自申请者摘要)：长期目标 本研究旨在明确脑内视觉信号的分子基础 哺乳动物的视锥感光细胞。具体目标是审查潜力 三种选择的锥体信号的作用机制差异 与视杆细胞相比的成分：视锥视色素、视锥细胞 CGMP磷酸二酯酶和锥形鸟苷酸环化酶。视觉效果 将检查颜料的漂白情况、活化度 转导蛋白，以及与阻滞素的相互作用。CGMP 将评估磷酸二酯酶的内在活性，非催化 CGMP控制活性，G蛋白控制激活和关闭 脱下来。鸟粪酰环化酶将被检查其内在的差异。 活性和调节酶活性的机制。生化 寻找可能解释为什么哺乳动物锥体细胞较少的机制 敏感，超极化更快，幅度更小，并适应 在信号形状几乎没有变化的情况下，在更大的光通量范围内 与杆状反应相比较。

DESCRIPTION (Adapted from applicant's abstract): The long term goal of this research is to define the molecular basis of visual signaling in mammalian cone photoreceptors. Specific aims are to examine potential mechanistic differences in function of three selected cone signaling components compared to those in rods: the cone visual pigments, the cone cGMP phosphodiesterase, and the cone guanylyl cyclases. The visual pigments will be examined for their bleaching profile, activation of transducins, and interactions with arrestins. The cGMP phosphodiesterase will be assessed for intrinsic activity, non-catalytic cGMP control of activity, and G-protein control of activation and shut- off. The guanylyl cyclases will be examined for differences in intrinsic activity and mechanisms that regulate enzymatic activity. Biochemical mechanisms are sought that might explain why mammalian cones are less sensitive, hyperpolarize more rapidly with smaller amplitudes, and adapt over a larger range of light fluence with little change in signal shape in comparison with rod responses.