VOLUME REGULATION IN NORMAL AND CATARACTOUS LENSES

我们希望了解正常的生理特性， 透镜这些特性如何赋予调节 细胞体积，从而保持透明性。 此外，委员会认为， 透镜位于房水和玻璃体之间 在控制这两种体液的成分中起着某种作用。 在 透镜失去其控制细胞的能力 体积和细胞内环境的组成，因此 形成白内障。 我们希望了解这些变化， 正常的生理特性，这些特性是丧失 透明 因为透镜是一种合胞体组织， 对其正常生理特性的理解仍存在问题。 在透镜中似乎有不止一种类型的细胞， 因为它是一个snycytium，运输由一种类型的细胞在一个 位置影响细胞质和膜的组成 在其他地方的其他类型的细胞中的通量。 从而 要了解透镜的整体宏观性质， 表征以下各项的更微观性质：（i） 膜转运特性;（ii）空间定位 这些膜运输参数;（iii）相互联系 透镜细胞通过低电阻间隙连接;和（iv）小的 透镜纤维细胞之间的细胞外通路。 为了表征这些微观性质，我们建议 为了利用细胞内微电极来研究电压， 流体静压和细胞质的离子组成。 此外，我们将使用阻抗技术来表征 电流的无源路径以及这些路径中的一些如何 受管制的（例如，间隙连接电导或膜 电导）。 我们将研究细胞外电流， 并诱导，使用大面积贴片移液器和振动 探针 我们将分离前上皮和纤维 细胞膜囊泡，以研究其运输特性。 最后，我们将使用基于结构的透镜计算机模型 将微观性质与宏观性质联系起来 生理特性

We wish to understand the normal physiological properties of the lens and how these properties confer the ability to regulate cellular volume and thereby maintain transparancy. Moreover, the lens sits between the aqueous and vitreous where it likely has some role in controlling the composition of these two humors. In certain circumstances the lens losses its ability to control cell volume and the composition of the intracellular milieu, whereupon a cataract is formed. We hope to understand those changes in normal physiological properties which underlie the loss of transparancy. Because the lens is a syncytial tissue, there are some special proglems in understanding its normal physiological properties. There appears to be more than one type of cell in the lens but, because it is a snycytium, transport by one type of cell in one location affects the composition of cytoplasm and membrane fluxes in other types of cells in other locations. Thus, to understand the overall macroscopic properties of the lens we must characterize the more microscopic properties of: (i) the membrane transport properties; (ii) the spatial localization of these membrane transport parameters; (iii) the interconnection of lens cells by low resistance gap junctions; and (iv) the small extracellular path between lens fiber cells. In order to characterize these microscopic properties, we propose to utilize intracellular microelectrodes to study voltage, hydrostatic pressure and ionic composition of the cytoplasm. Moreover, we will use impedance techniques to characterize the passive paths for current flow and how some of these paths are regulated (e.g., gap junctional conductance or membrane conductance). We will study extracellular currents, both natural and induced, using large area patch pipettes and the vibrating probe. And we will isolate the anterior epithelium as well as fiber cell membrane vesicles to study their transport properties. Lastly, we will use structurally based computer models of the lens to relate the microscopic properties to the overall macroscopic physiological properties.