REGULATION OF PHOTORECEPTORS SPECTRAL SENSITIVITY

这些研究的目标是阐明决定 单个感光细胞的光谱灵敏度。总体而言, 感光器的光谱灵敏度将取决于 视觉色素的表达及其对色素的吸收性能。 这两个方面都没有得到很好的理解。一种视觉色素 光谱调谐是由生色团的扰动产生的 特效性视神经。这项建议的第一个目标是找出如何和 视蛋白扰乱发色团以调节其吸收。我的 方法将是表征孤立的光谱敏感性 火蜥蜴和金鱼以前的杆状和圆锥体电生理 在用化学修饰的方法取代它们的天然发色团之后 视网膜类似物。使用一系列的视网膜双水类似物，我们将 定位与视蛋白相互作用的发色部位。第二 目的是找出一个细胞是否可以表达多个视蛋白和 是否所有的视蛋白都形成了功能色素。尽管一个人 光感受器被认为只表达一种类型的视蛋白，即 有证据表明某些感光器违反了这一规则。我们会 两种功能性视蛋白在豚鼠视锥细胞和视锥细胞中的存在试验 通过测量细胞的光谱敏感度，在火蜥蜴锥体中放置三个 暴露在强烈的漂白光中前后。《光谱》 漂白灯的组成要仔细选择，这样才能 颜料类型优先漂白。更多证据表明 将使用以下方法获得多个OPTIN表达 免疫组织化学和分子生物学探针。第三个目标是 为了研究光感受器改变类型的能力 在他们表达的视线中。我们将测量锥体的光谱灵敏度 在不同年龄的火蜥蜴和冬季比目鱼中观察它们的 色素含量随时间变化。这些研究的结果 这项研究可能对调控人类健康具有发展意义 视锥细胞密度和视锥细胞特异性神经回路的形成 视网膜。这些研究的长期目标是了解 视网膜编码波长携带的视觉信息并探索 潜在机制的可塑性。

The goal of these studies is to elucidate factors that determine the spectral sensitivities of individual photoreceptor cells. In general, a photoreceptor's spectral sensitivity will depend upon the type of visual pigment expressed and the absorption properties of the pigment. Neither of these aspects is well understood. A visual pigment's spectral tuning is produced by perturbations of the chromophore by its specific opsin. The first aim of this proposal is to find out how and where opsin perturbs the chromophore to tune its absorption. My approach will be to characterize the spectral sensitivities of isolated rods and cones of salamander and goldfish electrophysiologically before and after replacing their native chromophore with chemically modified retinal analogs. Using a series of dihydroretinal analogs, we will localize the chromophoric sites that interact with opsin. The second aim is to find out whether a cell can express multiple opsins and whether all opsins form functional pigments. Although an individual photoreceptor is thought to express only one type of opsin, there is evidence to suggest that some photoreceptors violate this rule. We will test for the presence of two functional opsins in guinea pig cones and three in salamander cones by measuring the cell's spectral sensitivity before and after exposure to an intense bleaching light. The spectral composition of the bleaching light will be carefully chosen so that one pigment type is bleached preferentially. Additional evidence that multiple opsins are expressed will be obtained using immunohistochemical and molecular biological probes. The third aim is to investigate the ability of photoreceptors to change the type of opsin they express. We will measure the spectral sensitivities of cones in salamander and winter flounder at different ages to see if their pigment content changes as a function of time. The results of these studies could have developmental significance for the regulation of cone density and the formation of cone-specific neural circuits in the retina. The long term goal of these studies is to understand how the retina encodes visual information carried by wavelength and to explore the plasticity of the underlying mechanisms.