SINGLE CHANNEL BASIS FOR CAMP DEPENDENT CHLORIDE CURRENT

营相关氯化物电流的单通道基础

• 批准号: 2145945
• 负责人: Sarah Garber
• 金额: $ 9.96万
• 依托单位: ALLEGHENY UNIVERSITY OF HEALTH SCIENCES
• 依托单位国家: 美国
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-09-30 至 1996-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2145945
• 关键词: apical membrane; calcium; chloride channels; cyclic AMP; epithelium; membrane permeability; membrane proteins; protein kinase; second messengers; secretion; voltage /patch clamp

Chloride transport plays a major role in the secretion of salts and fluids and in response to osmotic challenge. Fluid secretion in epithelial cells is modulated by the second messenger cAMP. The regulation of cAMP- dependent Cl- channels on the apical membrane of secretory epithelia contributes to the rate determining step for fluid secretion in these cells. This cAMP-dependent cl- transport is disrupted in Cystic Fibrosis (CF), a human genetic disease. Several cAMP-dependent cl- channels, whose activity may underlie macroscopic Cl- conductance, have been described in epithelial cells, under different experimental conditions. Two channels of primary interest are a large (40-45 pS), outwardly rectifying Cl- channel and a small (8-10 pS), linear Cl- channel. The activity of both of these channels is increased by cAMP-dependent mechanisms. The relationship between cAMP- dependent single channel and macroscopic Cl- current will be addressed by asking: What single Cl- channel activity can be identified in the presence of cAMP? Can the properties of one specific cAMP-dependent single channel activity account for the properties of the macroscopic current? These questions will be addressed as simultaneously recording cAMP- dependent single Cl- channel activity and macroscopic Cl- current. Once the ion channel(s) involved have been identified, their selectivity, permeation and kinetic properties, and pharmacological profile of their ion channel(s) will be characterized. Possible interactions between cAMP- and Ca++-dependent second messenger systems on single channel and macroscopic Cl- current activity will also be investigated. In the broad prospective, this project will address the physiological role of Cl- channels by elucidating the basic properties and regulatory mechanisms of Cl- channels at the single channel and macroscopic levels. The intimate knowledge of these properties will help to bridge the gaps between the molecular and cellular levels of secretory physiology. Thus, by identifying the underlying molecular events of cAMP-dependent Cl- transport in epithelial cells, we will be able to further the understanding of the role of these ion channel proteins play in fluid secretion. This will also provide valuable insight into the mechanistic basis of abnormal fluid secretion in Cystic Fibrosis.

氯离子运输在盐和液体的分泌中起着重要作用 并应对渗透挑战。 上皮细胞的液体分泌 受第二信使 cAMP 调节。 cAMP-的调节 分泌上皮细胞顶膜上依赖的氯离子通道 有助于这些中液体分泌的速率决定步骤 细胞。 这种 cAMP 依赖性 cl- 转运在囊性纤维化中被破坏 (CF)，一种人类遗传病。 几种 cAMP 依赖性 cl- 通道，其活性可能是 宏观 Cl- 电导，已在上皮细胞中得到描述， 在不同的实验条件下。 主要感兴趣的两个渠道 是一个大的 (40-45 pS)、向外整流的 Cl- 通道和一个小的 (8-10 pS) pS)，线性 Cl-通道。 这两个通道的活动是 通过 cAMP 依赖性机制增加。 cAMP-之间的关系 相关的单通道和宏观 Cl- 电流将通过以下方式解决 询问：可以在 cAMP 的存在？一种特定的 cAMP 依赖性单链的特性 渠道活动占宏观当前的属性？ 这些问题将通过同时记录 cAMP-来解决 依赖的单一 Cl- 通道活动和宏观 Cl- 电流。 一次 所涉及的离子通道已被识别，它们的选择性， 其渗透和动力学特性及其药理学特征 将表征离子通道。 cAMP-之间可能存在的相互作用 和 Ca++ 依赖的单通道第二信使系统 宏观Cl-电流活动也将被研究。 从更广泛的角度来看，该项目将解决生理作用 通过阐明 Cl- 通道的基本属性和监管 Cl-通道在单通道和宏观水平上的作用机制。 对这些特性的深入了解将有助于弥合差距 分泌生理学的分子和细胞水平之间的关系。 因此， 通过识别 cAMP 依赖性 Cl- 的潜在分子事件 上皮细胞中的转运，我们将能够进一步 了解这些离子通道蛋白在液体中的作用 分泌。 这也将为机制提供有价值的见解 囊性纤维化异常液体分泌的基础。