TEAR GLAND FLUID FORMATION

泪膜对于视觉图像的质量是必要的， 用于保护眼表面。 干眼症是主要的 眼发病率的原因，和水的缺陷， 泪膜的组成部分，由泪腺产生 腺体，已牵连在很大比例的干眼 例 人们对这种疾病的正常机制知之甚少。 泪液分泌功能 部分原因是， 缺陷尚未确定，目前的干眼治疗 必须依靠人工泪液替代。 拟议的研究将描述一个最近发现的 泪腺泡细胞功能方面，刺激相关 钠泵酶Na，K-ATP酶的再分布。 在 泪腺泡细胞，Na，K-ATPase，Na/H逆向转运体，Cl/HCO 3 反向转运蛋白和毒蕈碱乙酰胆碱受体存在于 基底外侧膜，在至少两个基本上 不同类型的细胞质池，第一个相对丰富， 基底-外侧膜表达的成分， Na，K-ATPase，第二种Na，K-ATPase相对较丰富。 在毒蕈碱受体激活后，Na，K-ATP酶和 其他成分从细胞质库中被动员， 转移到基底侧膜。 现有数据 这与这种整体易位的假设一致， 分两步进行：从第一个细胞质池到第二个细胞质池， 底侧膜，并从第二池到第一。 提出了Na，K-ATP酶信号识别的实验 易位，描绘所涉及的步骤的顺序， 确定细胞质池的功能特性， Na，K-ATPase，并阐明它们之间的关系 易位现象和基底-侧膜再循环。 实验设计将利用从大鼠分离的完整腺泡 眶外泪腺 这些结构保留了细胞：细胞 交界处和正常的顶端与基底侧极性。 因为 腺泡可以在短期培养中维持长达2天， 将有可能进行代谢，流体相，和表面， 标记程序，然后对腺泡进行多维 亚细胞分级分离程序，包括差异 沉降、密度梯度离心和分配， 水相聚合物系统，解决了一系列的 亚细胞膜群体。 与此同时， 可能将形态学和免疫细胞化学 结果与分析分馏数据。

The tear film is necessary for the quality of the visual image and for protection of the ocular surface. Dry eye states are major causes of ocular morbidity, and deficiencies of the aqueous component of the tear film, which is produced by the lacrimal glands, have been implicated in a large proportion of dry eye cases. Little has been known about the normal mechanisms of lacrimal secretory function. In part because specific functional defects have not yet been identified, current dry eye treatments must rely on replacement with artificial tears. The proposed studies will characterize a recently discovered aspect of lacrimal acinar cell function, stimulation-associated redistribution of the sodium pump enzyme, Na,K-ATPase. In the lacrimal acinar cell, Na,K-ATPase, Na/H antiporters, Cl/HCO3 antiporters, and muscarinic acetylcholine receptors are present in the basal-lateral membranes, and in at least two fundamentally different kinds of cytoplasmic pools, the first relatively richer in the basal-lateral membrane-expressed constituents other than Na,K-ATPase, and the second relatively richer in Na,K-ATPase. Following activation of muscarininc receptors, Na,K-ATPase and other constituents are mobilized from the cytoplasmic pools and translocated to the basal-lateral membranes. Available data are consistent with the hypothesis that this overall translocation procedes in two steps: from the first cytoplasmic pool to the basal-lateral membrane, and from the second pool to the first. Experiments are proposed to identify signals for Na,K-ATPase translocation, to delineate the sequence of steps involved, to identify the functional properties of the cytoplasmic pools of Na,K-ATPase, and to clarify the relationship between these translocation phenomena and basal-lateral membrane recycling. The experimental design will utilize intact acini isolated from rat exorbital lacrimal glands. These structures retain cell:cell junctions and normal apical vs basal-lateral polarity. Because the acini can be maintained in short-term culture for up to 2 days, it will be possible to perform metabolic-, fluid phase-, and surface- labeling procedures, then subect the acini to a multidimensional subcellular fractionation procedure, incorporating differential sedimentation, density gradient centrifugation, and partitioning in aqueous polymer phase systems, which resolves a series of subcellular membrane populations. At the same time, it will be possible to correlate morphological and immunocytochemical results with the analytical fractionation data.