SINGLE CHANNEL BASIS FOR CAMP-DEPENDENT CL- CURRENT

营地相关 CL 电流的单通道基础

• 批准号: 3248076
• 负责人: Sarah Garber
• 金额: $ 10.16万
• 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 1995-09-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3248076
• 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.

氯化物的运输在盐分和液体的分泌中起主要作用。 作为对渗透挑战的回应。上皮细胞的液体分泌 是由第二信使阵营调制的。对营房的监管- 分泌上皮细胞顶膜上的依赖氯离子通道 有助于体液分泌的速度决定步骤 细胞。囊性纤维化中这种cAMP依赖的氯离子转运被破坏 (Cf)，一种人类遗传病。 几个cAMP依赖的氯离子通道，它们的活动可能是 宏观氯离子电导，已经在上皮细胞中被描述， 在不同的实验条件下。两个主要感兴趣的渠道 是一个大的(40-45ps)向外整流的氯离子通道和一个小的(8-10 PS)，线性氯离子通道。这两个通道的活动都是 通过cAMP依赖机制增加。阵营之间的关系- 相关的单通道和宏观氯电流将通过以下方式解决 问：什么单一的氯离子通道活性可以在 露营的存在吗？一种特定的cAMP依赖单链的性质 通道活动可以解释宏观电流的特性吗？ 这些问题将作为同时记录夏令营- 依赖于单个氯离子通道活性和宏观氯离子电流。一次 已经确定了涉及的离子通道(S)，它们的选择性， 其透皮吸收、动力学性质及药理研究进展 离子通道(S)将被表征。CAMP之间可能的相互作用- 单通道上依赖钙离子的第二信使系统和 宏观的氯离子电流活性也将被调查。 在广阔的前景中，这个项目将解决生理作用 通过阐明氯离子通道的基本性质和调节 氯离子通道在单通道和宏观水平上的机制。 对这些特性的深入了解将有助于弥合差距 在分泌生理学的分子和细胞水平之间。因此， 通过鉴定cAMP依赖的氯-的潜在分子事件 在上皮细胞中的运输，我们将能够进一步 了解这些离子通道蛋白在体液中的作用 分泌物。这也将提供对机制的有价值的洞察 囊性纤维化液体分泌异常的基础。