REGULATION OF PHI AND FLUID FLUX IN CORNEAL ENDOTHELIUM

角膜的水化和透明度取决于离子和液体。 角膜内皮的运输特性。流体从 基质到房水显然与钠的净转运有关 和HCO3，对浴液的pH很敏感。一个完整的 然而，离子耦合流体输运的模型还不可用。自.以来 胞外和胞内[HCO3]由胞外和胞内[HCO3]决定 细胞内pH(pho和phi)，可以合理地认为 HCO3运输模型需要了解PHI的调节。 这一观点得到了研究的支持，该研究表明，添加的药物 已知影响phi调节(阿米洛利和DIDS)也抑制 内皮细胞液体运输。这项研究建议确定和 描述存在的PHI调节和HCO3-转运机制 利用pH值对新鲜和培养的牛角膜内皮细胞进行培养 灵敏的细胞内荧光探针。单元格也将被 生长在滤器支架上，允许独立进入根尖和基底部 表面以确定HCO3运输的位置 并建立了一个完整的跨内皮细胞HCO3- 运输。跨内皮液的分泌也可以通过 过滤培养物，以便HCO3-运输机制对 流体传输和传输机制-即速率限制 可以确定流体的流量。长期目标是确定代理人或 刺激HCO3运输并测试其能力的条件 还可以刺激体液分泌。最后，手术后的标本 福赫氏内皮营养不良症将获得和pH调节和 将测试HCO3-运输能力，以确定是否和 泵功能在这种疾病中是如何错乱的。一旦交通工具 缺陷被确定，长期目标是测试符合以下条件的药物 刺激它或抑制相反的转运机制的药物 以增强这种病变内皮细胞的液体分泌。

Corneal hydration and transparency are dependent on the ion and fluid transport properties of the corneal endothelium. Fluid transport from stroma to aqueous humor is apparently coupled to the net transport of Na and HCO3 and is sensitive to the pH of the bathing solution. A complete model for ion coupled fluid transport however, is not available. Since extra- and intracellular [HCO3] are determined by extra- and intracellular pH (pHo and pHi), it is reasonable to suggest that any model of HCO3 transport will require an understanding of pHi regulation. This notion is supported by work showing that additions of drugs which are known to influence pHi regulation (amiloride and DIDS) also inhibit endothelial fluid transport. This study proposes to identify and characterize the pHi regulatory and HCO3- transport mechanisms present in fresh and cultured bovine corneal endothelial cells by utilizing the pH sensitive intracellular fluorescent probe, BCECF. Cells will also be grown on filter supports to allow independent access to apical and basal surfaces in order to determine the locations of the HCO3 transport mechanisms and establish a complete model for transendothelial HCO3- transport. Transendothelial fluid secretion can also be measured across filter cultures so that the HCO3- transport mechanisms essential for fluid transport and the transport mechanism-that is rate limiting for fluid flux can be identified. A long term goal is to identify agents or conditions that stimulate HCO3- transport and test their ability to stimulate fluid secretion as well. Lastly, post-surgical specimens of Fuch's Endothelial Dystrophy will be obtained and the pH regulatory and HCO3- transport capacities will be tested in order to determine if and how pump function is deranged in this disease. Once the transport deficit is identified, the long term goal is to test drugs which stimulate it or drugs that inhibit an opposing transport mechanism in order to enhance fluid secretion in this diseased endothelia.