REGULATION OF PROXIMAL TUBULE BASOLATERAL KATP CHANNELS

近端肾小管基底外侧 KATP 通道的调节

基本信息

批准号：
6489623
负责人：
CRAIG G HURWITZ
金额：
$ 4.56万
依托单位：
UNIVERSITY OF VERMONT & ST AGRIC COLLEGE
依托单位国家：
美国
项目类别：
财政年份：
2000
资助国家：
美国
起止时间：
2000-06-01 至
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/6489623
关键词：
Urodela adenosine triphosphate basolateral membrane epithelium potassium channel renal tubular transport tissue /cell culture voltage /patch clamp

项目摘要

The long-term objective of this project is to understand the nature of ion channel conductances in the basolateral membrane (BLM) of the renal proximal tubule (PT). ATP-sensitive potassium (KATP) channels underlie the dominant conductance (G) of the BLM. GK-ATP is a critical regulator of transport since the opening of BLM KATP channels maintains the driving force and provides a permeability required for continued epithelial transport. Therefore, in Aim I the biophysical characteristics of the ensemble conductance through BLM KATP channels will be determined, and other ion channels that contribute to GBLM will be identified. Since KATP channel activity is coupled to that of the Na+ pump, exploring the behavior of GK-ATP is crucial to understanding the regulation of transport in the PT. Therefore, in Aim 2 the regulation of the ensemble BLM KATP conductance by key cellular signaling pathways will be explored. This proposal focuses on defining the characteristics of the aggregate BLM KATP conductance by voltage clamping a large area of membrane (macropatch). The incentive to make macropatches on the BLM is clear: whole cell voltage clamping does not distinguish apical from BLM currents, and single channel recordings alone do not provide the signal to noise ratio, ease of analysis, or overall perspective that can be realized with macropatches. Although macropatches have been used in the study of cells with relatively smooth membranes (e.g., neurons), this approach has never been applied to epithelia due to technical obstacles. Therefore, the plan to exploit macropatches to explore GK ATP represents a novel, powerful approach that will allow reproducible and robust recordings of ensemble currents from the BLM that are unprecedented. The ultimate goal of these studies is to deepen our understanding of epithelial ion channels and how they are coupled to other membrane transport elements in coordinating overall cellular transport in the PT. Clinically, this work will provide insights relevant to hypertension, potassium balance, acute renal failure, and diabetes mellitus.

该项目的长期目标是了解肾近端小管（PT）基底外侧膜（BLM）中离子通道电导的性质。 ATP敏感的钾（KATP）通道是BLM的主要电导（G）。 GK-ATP是运输的关键调节器，因为BLM KATP通道的开放保持了驱动力，并提供了持续上皮运输所需的渗透性。因此，将确定通过BLM KATP通道的集合电导的生物物理特性，并确定其他有助于GBLM的离子通道。由于KATP通道活性与Na+泵的活性耦合，因此探索GK-ATP的行为对于理解PT中转运的调节至关重要。因此，将探索AIM 2通过关键细胞信号通路对集合BLM KATP电导的调节。该提案的重点是通过夹紧大面积的膜（macropatch）来定义骨料BLM KATP电导的特性。在BLM上进行宏观捕获的动机很明显：全细胞电压夹紧并不能区分顶端与BLM电流，仅单个通道记录并不能提供信号与噪声比，易于分析或可以通过宏观捕获来实现的总体视角。尽管宏观捕获了膜的研究，该细胞具有相对光滑的膜（例如神经元），但由于技术障碍，这种方法从未应用于上皮。因此，利用宏观探索GK ATP的计划代表了一种新颖，有力的方法，它将允许从BLM中可重现和可靠的集合电流记录，而BLM的前所未有。这些研究的最终目的是加深我们对上皮离子通道的理解，以及它们如何与其他膜运输元件耦合，以协调PT的总体细胞运输。在临床上，这项工作将提供与高血压，钾平衡，急性肾衰竭和糖尿病有关的见解。