VOLUME REGULATION IN CORNEAL ENDOTHELIUM

角膜内皮的体积调节

• 批准号: 2165380
• 负责人: SANGLY P SRINIVAS
• 金额: $ 12.57万
• 依托单位: UNIVERSITY OF CALIFORNIA BERKELEY
• 依托单位国家: 美国
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-09-30 至 1998-09-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2165380
• 关键词: acid base balance; aminoacid; animal tissue; biological signal transduction; cell morphology; cell osmotic pressure; corneal endothelium; fluorescent dye /probe; high performance liquid chromatography; hyperglycemia; hypoxia; intraocular aqueous flow; intraocular pressure; ion transport; laboratory rabbit; light scattering; nuclear magnetic resonance spectroscopy; physiologic stressor; second messengers; sorbitol; water flow

Maintenance of cell volume is a homeostatic process expressed in all animal cells. The necessary water movement across the plasma membrane is coupled to solute transport mechanisms that are also involved in other cellular activities such as the accumulation of glucose, pHi regulation or vectorial fluid transport. The corneal endothelium is endowed with an active ion pump mechanism responsible for vectorial fluid transport and hence the maintenance of corneal hydration, a determinant of corneal transparency. Since this fluid transport and cell volume regulation must be intertwined, it is imperative to establish the mechanisms of volume maintenance and regulation to obtain a complete understanding of the fluid transport. In addition, it is of clinical significance to understand how fluid transport is affected during times of osmotic stress such as during contact lens wear and diabetes. The focus of this study is to establish the principles of volume regulation upon acute and sustained disturbances leading to short and long term volume regulations, respectively/ Short term volume regulation will be studied by following changes in cell volume and intracellular ionic activities to identify the mechanisms and second messengers involved. Experiments will employ anisosmotic perturbations, acidosis, hypoxia, ion substitutions and transport-specific inhibitors. Long term volume regulation will be examined in the context of adaptation to sustained anisosmotic loads by adjusting the levels of organic osmolytes (such as amino acids, myo-inositol and sorbitol). Isolated in vitro rabbit corneas and cultured bovine endothelial cells that are confluent and polarized on either glass coverslips or permeable supports will be used. The dynamics of cell volume will be measured using athe sensitive light scattering technique and by following the concentration of a fluorescent dye used as a volume marker. The long term goal of this study is to understand the interaction of the fluid transport, pHi regulation and volume regulation activities of the corneal endothelium under normal conditions and during metabolic stress, hyperglycemia and anisosmotic loads.

细胞体积的维持是所有动物中都表达的稳态过程 细胞。穿过质膜的必要水运动是耦合的 溶质转运机制也涉及其他细胞 葡萄糖积累、pHi 调节或矢量等活动 流体输送。角膜内皮被赋予活性离子 泵机制负责矢量流体输送，因此 维持角膜水合作用，这是角膜透明度的决定因素。 由于这种液体运输和细胞体积调节必须交织在一起， 建立保量机制势在必行 调节以获得对流体输送的完整了解。在 此外，了解液体运输的方式也具有临床意义。 在渗透压期间（例如佩戴隐形眼镜期间）会受到影响 和糖尿病。本研究的重点是确立以下原则： 急性和持续干扰导致短暂的音量调节 和长期交易量规定/短期交易量 将通过以下细胞体积的变化来研究调节 细胞内离子活动以确定机制和第二 参与的使者。实验将采用不等渗扰动， 酸中毒、缺氧、离子替代和转运特异性抑制剂。 将在适应的背景下审查长期的音量调节 通过调节有机渗透剂的水平来维持不等渗负荷 （如氨基酸、肌醇和山梨醇）。离体兔 角膜和培养的牛内皮细胞汇合并 将使用玻璃盖玻片或可渗透支撑物上的偏振。 将使用敏感光测量细胞体积的动态 散射技术并通过跟踪荧光浓度 用作体积标记的染料。这项研究的长期目标是 了解流体运输、pHi 调节和 正常情况下角膜内皮的体积调节活动 条件和代谢应激、高血糖和不等渗期间 负载。