CGMP MEDIATED REGULATION OF CILIARY EPITHELIAL TRANSPORT

CGMP 介导的睫状上皮运输调节

• 批准号: 2164733
• 负责人: MORTIMER MORDECAI CIVAN
• 金额: $ 23.25万
• 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/2164733
• 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 On the basis of published data and our unpublished observations, we have formulated a hypothesis concerning the roles of cGMP in regulating the rate of aqueous humor secretion.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 介导的递质在 调节睫状上皮功能。在系统层面上， 一方面是利钠肽（ANP 和 BNP）和 NO，另一方面是血管紧张素 II（AII）在另一端，形成一对平衡且相对的发射器 调节血管舒缩；利尿钠肽和 AII 也相互对抗 其他调节尿钠。这种综合平衡部分是 通过改变细胞内 cGMP 浓度来介导 （环鸟苷-3',5'-单磷酸），通过利尿钠增加 肽和 NO 并被 AII 减少。公布的数据表明， 睫状上皮可以对所有这些做出反应和/或具有受体 发射机。此外，在细胞内水平上，这两个循环 核苷酸 cGMP 和 cAMP（环腺苷-3',5'-单磷酸）似乎 构成一对额外的平衡和对立的信使， 调节房水的分泌。根据已公布的数据 和我们未发表的观察结果，我们提出了一个假设 关于 cGMP 在调节房水速率中的作用 分泌。我们认为 cGMP 的主要作用是逆转 cAMP- 介导的 Na、K 交换泵抑制，涉及两种蛋白质 非色素性睫状上皮细胞的激酶 A 和 DARPP-32。 当前计划的实验方法将是测量两者 睫状上皮的跨上皮和跨膜运输。我们 应进行跨上皮测量和细胞贴附补片 夹住兔子的完整睫状上皮（其 特征已被明确定义）和猫（其属性是 可能更接近灵长类动物）。我们还将学习小学和/或 非色素和色素睫状上皮细胞的连续线 （人类、牛、兔和猫来源）通过膜片钳 常规全细胞、穿孔全细胞、细胞贴壁和切除- 补丁模式。 研究计划的具体目标是： (1) 确定 每个递质（ANP、BNP、AII 和 NO）的影响分别，以及 这些发射器的相互作用； (2) 检验是否存在交互作用 递质和第二信使（cGMP 和 cAMP）之间，以及 cAMP 和 cGMP 本身之间，符合所提出的假设；和 (3)确定环核苷酸调节作用是否被介导 由假设的运输机制。