ERYTHROCYTE POTASSIUM TRANSPORT AND VOLUME REGULATION

长期目标是为设计提供知识基础， 诱导红细胞慢性、可控肿胀的方法 Hb S纯合子个体。 红细胞的低阳离子渗透性 相对于其他组织，这使得提出药理学 诱导红细胞肿胀的方法。 然而，在这些战略之前， 可以设计，这将是必要的了解如何SS红细胞 会对增加其体积的尝试做出反应。 此外，动物模型的 人SS红细胞体积调节在开发 解决体内细胞体积操纵问题的方法。 有 有证据表明，人SS红细胞的渗透性肿胀导致激活 一个依赖C1的钾转运系统， 最近在兔子红细胞中观察到。 这个K外排系统是 可能负责调节细胞体积， 了解这个系统，以优化策略， 细胞 第一个目的是比较钾外流的特点（使用 86 Rb作为示踪剂），以测定氧化的人SS和兔红细胞中的 评价家兔作为动物模型。 另一个目标是找到 不可逆作用的肿胀刺激钾外流抑制剂;如 抑制剂将使我们能够确定系统是否真的 对细胞体积调节至关重要。 不可逆的K抑制剂 外排也可能导致体外治疗， 细胞肿胀 为了确定催化 肿胀刺激的钾离子外流，我们将产生单克隆抗体， 使用筛选程序来选择抑制K 流出 这种抗体在未来的分子水平上将是非常有价值的 在运输系统上工作。 该提案的最后一个主要目的是 开始表征成熟过程中阳离子运输的调节 网状细胞 阳离子运输发生了非常显著的变化 在网织红细胞成熟过程中，了解这些变化将 在设计长期操纵红色的策略时至关重要 细胞体积

The long range goal is to provide the knowledge base for the design of methods for inducing chronic, controlled swelling of red cells in individuals homozygous for Hb S. The low cation permeability of red cells relative to other tissues makes it feasible to propose pharmacologic methods for inducing red cell swelling. However, before such strategies can be designed, it will be necessary to understand how the SS red cell would respond to attempts to increase its volume. Also, an animal model of human SS red cell volume regulation would be very useful in developing approaches to the problem of in vivo cell volume manipulation. There is evidence that osmotic swelling of human SS red cells causes the activation of a C1-dependent K transport system that is very similar to one that we have recently observed in rabbit red cells. This K efflux system is probably responsible for cell volume regulation, and it will be essential to understand this system in order to optimize strategies for swelling the cells. The first aim is to compare the characteristics of K efflux (using 86Rb as tracer) in oxygenated human SS and rabbit red cells, in order to evaluate the rabbit as an animal model. Another aim is to find irreversibly acting inhibitors of the swelling-stimulated K efflux; such inhibitors will allow us to determine whether the system is really essential for cell volume regulation. Irreversible inhibitors of the K efflux could also lead to extracorporeal treatments that would cause red cell swelling. In order to identify the transport protein that catalyzes the swelling-stimulated K efflux, we will raise monoclonal antibodies, using a screening procedure to select antibodies that inhibit the K efflux. Such antibodies would be very valuable in future molecular-level work on the transport system. The last major aim of the proposal is to begin to characterize the regulation of cation transport in the maturing reticulocyte. Very significant changes in cation transport take place during reticulocyte maturation, and an understanding of these changes will be essential in the design of strategies for long-term manipulation of red cell volume.