REGULATION OF PHI AND FLUID FLUX IN CORNEAL ENDOTHELIUM

角膜水合作用和透明度取决于离子和液体 角膜内皮的运输特性。 液体运输从 间质到房水显然与Na+的净转运有关 和HCO 3，并且对浴液的pH敏感。 一个完整 然而，离子耦合流体输运的模型是不可用的。 以来 细胞外和细胞内[HCO 3]由细胞外和 细胞内pH值（pHo和pHi），合理的建议是， HCO 3运输模型需要了解pHi调节。 这一概念得到了工作的支持，工作表明， 已知影响pHi调节（阿米洛利和DIDS）也抑制 内皮液体转运 这项研究旨在确定和 表征pHi调节和HCO 3运输机制存在于 新鲜培养的牛角膜内皮细胞， 敏感的细胞内荧光探针BCECF。 细胞也将 生长在过滤器支架上，允许独立进入顶端和基底部 以确定HCO 3运输的位置 机制，并建立一个完整的模型，跨内皮HCO 3- 运输 跨内皮液体分泌也可以通过 过滤培养，使HCO 3-运输机制必不可少的 流体传输和传输机制-即速率限制 可以识别流体通量。 一个长期目标是确定代理人或 刺激HCO 3-运输的条件，并测试它们的能力， 刺激体液分泌。 最后，手术后的标本 将获得Fuch内皮营养不良，并将pH调节和 将测试HCO 3-输送能力，以确定 这种疾病中泵功能是如何紊乱的 一旦运输 确定了缺陷，长期目标是测试药物， 刺激它或药物，抑制相反的运输机制， 以增强患病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.