VISUAL RECEPTOR POTENTIALS

视觉感受器电位

• 批准号: 3260047
• 负责人: JOEL E BROWN
• 金额: $ 18.32万
• 依托单位: WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1983
• 资助国家: 美国
• 起止时间: 1983-07-01 至 1990-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3260047
• 关键词: calcium; electrical potential; electrophysiology; fresh water environment; guanosine triphosphate; high performance liquid chromatography; hydrolysis; inositol phosphates; isomer; light adaptations; lipid metabolism; membrane permeability; phosphatidylinositols; photochemistry; photostimulus; rhodopsin; saltwater environment; scintillation counter; stimulus /response; thin layer chromatography; visual photoreceptor

The long-term objectives of the research are to understand the cascades of reactions that mediate and modulate excitation in photoreceptors. Light is absorbed by rhodopsin, and the excitatory cascade ultimately induces a change in current that flows across the plasma membrane. The proposed research will examine several putative steps in that cascade. The action of a phospholipase on phosphatidylinositides has been proposed to be one step in the cascade. The research involves correlated electrophysiological and biochemical studies of: (1) the light-modulated metabolism of phosphoinositides and the water soluble hydrolysis products, the inositol polyphosphates; (2) the identification of the active inositol polyphosphate isomers; (3) the participation of calcium ions in the phosphoinositide metabolism; (4) the ability of exogenous compounds, such as phospholipase C and pp60src (the src gene product) to mimic or modulate excitation, and (5) the participation of GTP-binding proteins in the excitatory cascade. The biochemical studies involve the use of: HPLC to separate and identify the water soluble inositol polyphosphates, including the isomers;m TLC (and possible HPLC) to separate and identify phosphoinositides; and liquid scintillation counting to quantify the various fractions. Assays will be performed on single Limulus ventral eyes, and possibly on single photoreceptor cells. Intracellular recording of membrane voltage and voltage-clamp current will be used to monitor excitation electrophysiologically. The intracellular calcium ion concentration will be monitored by the aequorin luminesence technique.

研究的长期目标是了解 介导并调节光感受器激发的反应。 光是 被视紫红质吸收，兴奋性级联最终诱导A 流向质膜的电流变化。 提议 研究将研究该级联的几个推定步骤。 动作 磷脂酰肌醇上的磷脂酶已被认为是一种 踏入级联。 该研究涉及相关的电生理学 和生化研究：（1） 磷酸肌醇和水溶性水解产物，肌醇 多磷酸盐； （2）鉴定活性肌醇多磷酸盐 异构体； （3）钙离子参与磷酸肌醇 代谢; （4）外源化合物（例如磷脂酶C）的能力 和PP60SRC（SRC基因产物）以模仿或调节激发，（5） GTP结合蛋白参与兴奋性级联反应。 这 生化研究涉及：HPLC的使用以分离并确定 水溶性肌醇磷酸盐，包括异构体； m tlc（和 可能的HPLC）分离并识别磷酸肌醇；和液体 闪烁计数以量化各种分数。 测定将是 在单一limulus腹眼中进行，可能在 感光细胞。 膜电压的细胞内记录和 电压钳电流将用于监测激发 电生理学。 细胞内钙离子浓度将 可以通过Aquorin Luminesence技术监视。