CGMP MEDIATED REGULATION OF CILIARY EPITHELIAL TRANSPORT

CGMP 介导的睫状上皮运输调节

• 批准号: 2164734
• 负责人: MORTIMER MORDECAI CIVAN
• 金额: $ 21.9万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-08-01 至 1998-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2164734
• 关键词: angiotensin II; animal tissue; atrial natriuretic peptide; biological transport; cats; chloride channels; chlorine; cyclic AMP; cyclic GMP; epithelium; intraocular aqueous flow; ion transport; laboratory rabbit; membrane transport proteins; neurotransmitters; nitric oxide; potassium; second messengers; sodium potassium exchanging ATPase; uvea ciliary body; voltage /patch clamp

We propose to study the roles of cGMP and cGMP-mediated transmitters in regulating ciliary epithelial function. On a systemic level, the natriuretic peptides (ANP and BNP) and NO on the one hand, and angiotensin II (AII) on the other, form a pair of balancing and opposing transmitters regulating vasomotion; the natriuretic peptides and AII also oppose each other in regulating natriuresis. This integrative balance is partly mediated through changes in the intracellular concentration of cGMP (cyclic guanosine-3',5'-monophosphate), which is increased by natriuretic peptides and NO and decreased by AII. Published data indicate that the ciliary epithelium can respond and/or has receptors to all of these transmitters. Furthermore, on an intracellular level, the two cyclic nucleotides cGMP and cAMP (cyclic adenosine-3',5'-monophosphate) appear to constitute an additional pair of balancing and opposing messengers, regulating the secretion of aqueous humor. On the basis of published data and our unpublished observations, we have formulated a hypothesis concerning the roles of cGMP in regulating the rate of aqueous humor secretion. We propose that the major effect of cGMP is to reverse a cAMP- mediated inhibition of the Na,K-exchange pump, involving both protein kinase A and DARPP-32 of the non-pigmented ciliary epithelial cells. The experimental approach of the current program will be to measure both transepithelial and transmembrane transport by the ciliary epithelium. We shall perform transepithelial measurements and cell-attached patch clamping of the intact ciliary epithelium from both the rabbit (whose characteristics have been well defined) and the cat (whose properties are likely closer to those of primates). We shall also study primary and/or continuous lines of non-pigmented and pigmented ciliary epithelial cells (of human, bovine, rabbit and cat origin) by patch clamping in the conventional whole-cell, perforated whole-cell, cell-attached and excised- patch modes. The specific objectives of the research program are to: (1) determine the effects of each transmitter (ANP, BNP, AII, and NO) separately, and the interactions of these transmitters; (2) test whether the interactions between the transmitters and second messengers (cGMP and cAMP), and between cAMP and cGMP themselves, conform to the hypothesis proposed; and (3) determine whether the cyclic nucleotide-regulated effects are mediated by the transport mechanisms postulated.

我们建议研究CGMP和CGMP介导的发射机在 调节睫状上皮功能。在系统层面上 亚钠肽（ANP和BNP），一方面无，血管紧张素 II（AII）另一个，形成一对平衡和相反的发射器 调节血管症； Natriuretic肽和AII也反对 其他在调节纳特里雷SIS的方面。这种综合平衡部分是 通过CGMP细胞内浓度的变化介导 （循环鸟嘌呤-3'，5'单磷酸盐），纳特里疗法增加 肽和无AII减少。发布的数据表明 睫状上皮可以反应和/或具有所有这些受体 发射器。此外，在细胞内，两个环状 核苷酸CGMP和CAMP（环状腺苷-3'，5'-单磷酸盐）似乎 构成另外一对平衡和对立的使者， 调节幽默的分泌。根据已发布的数据 和我们未发表的观察结果，我们提出了一个假设 关于CGMP在调节水性幽默速率中的作用 分泌。我们建议CGMP的主要影响是扭转一个营地 介导的Na，K-Exchange泵的抑制作用，涉及两种蛋白 非色素纤毛上皮细胞的激酶A和DARPP-32。 当前程序的实验方法将是测量 纤毛上皮的跨层和跨膜运输。我们 应执行旋转测量和细胞跟踪贴片 从两只兔子的完整睫状上皮夹紧（其 特征已经很好地定义了）和猫（其特性是 可能更接近灵长类动物）。我们还将学习初级和/或 无色调和色素睫状上皮细胞的连续线 （人类，牛，兔子和猫的起源）通过贴片夹在 常规的全细胞，穿孔的全细胞，细胞连接和切除 - 补丁模式。 研究计划的具体目标是：（1）确定 每个发射器（ANP，BNP，AII和NO）的影响分别 这些发射机的相互作用； （2）测试是否相互作用 在发射机和第二使者（CGMP和CAMP）之间，以及 在营地和CGMP本身之间，符合提出的假设；和 （3）确定循环核苷酸调节作用是否介导 通过假定的运输机制。