Function and Regulation of HCN Channels in Sinoatrial Myocytes

窦房肌细胞HCN通道的功能和调控

基本信息

批准号：
7380345
负责人：
CATHERINE PROENZA
金额：
$ 34.36万
依托单位：
UNIVERSITY OF CONNECTICUT STORRS
依托单位国家：
美国
项目类别：
财政年份：
2008
资助国家：
美国
起止时间：
2008-01-15 至 2008-12-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7380345
关键词：
Action Potentials Address Adrenergic Receptor Agonist Back Cardiac Cells Communication Complex Cyclic AMP Cyclic AMP-Dependent Protein Kinases Cyclic Nucleotides Dependence Development Diastole Electrophysiology (science)Fire - disasters Frequencies Generations Goals Health Heart Heart Diseases Heart Rate Heart failure Human Hypertension Ion Channel Ischemia Kinetics Knockout Mice Maps Mediating Membrane Membrane Potentials Microscopy Modeling Molecular Mus Muscle Cells Nerve Neuromuscular Junction Neurons Neurotransmitter Receptor Norepinephrine Pacemakers Personal Satisfaction Play Process Proteins Rate Regulation Relative (related person)Rest Role Scaffolding Protein Shapes Signal Transduction Signaling Protein Sinoatrial Node Site Skeletal Muscle Sympathetic Nervous System System Techniques Testing Thinking Time Work base chronotropic fascinate fighting immunoaffinity chromatography mutant outcome forecast patch clamp phosphoric diester hydrolase postsynaptic receptor research study response voltage voltage clamp

项目摘要

DESCRIPTION (provided by applicant): Each beat of the heart begins as a spontaneous electrical depolarization of specialized pacemaker cells in the sinoatrial node. The sympathetic nervous system increases heart rate primarily by releasing norepinephrine from nerves that innervate the sinoatrial node. Within the sinoatrial myocytes, this aspect of the sympathetic fight-or-flight response requires communication between the 2 adrenergic receptors (2ARs) that respond to the norepinephrine and the ion channels that collectively control the timing and shape of action potentials. The long-term goal of this project is to understand the molecular machinery that produces and regulates pacemaker activity in sinoatrial myocytes. Experiments outlined in this proposal focus on some aspects of signaling between 2ARs and hyperpolarization-activated, cyclic nucleotide sensitive (HCN, or pacemaker) ion channels. HCN channels are activated by 2ARs and are thought to be critical both for setting the resting heart rate and for mediating the positive chronotropic effect of 2 agonists. However, the biophysical mechanisms for HCN channel involvement in pacemaking, and the functional and physical relationships between HCN channels and 2 adrenergic receptors are poorly understood. The working hypotheses to be tested in this project are that a leak current produced by HCN channels is critical for pacemaker activity in sinoatrial myocytes, and that sympathetic regulation of pacemaking requires a macromolecular signaling complex that contains 2ARs and HCN channels. These questions will be addressed using expressed HCN channels, acutely isolated murine sinoatrial myocytes and cultured sinoatrial myocytes. The principle techniques to be employed are patch clamp electrophysiology, confocal immunofluorescent microscopy, and immunoaffinity chromatography. There are three specific aims: (1) To understand the biophysical mechanisms for HCN channel activity during diastole, (2) To describe the functional relationships between 2ARs and HCN channels that control firing rate in sinoatrial myocytes, and (3) To determine the subcellular localization and physical interactions of proteins that participate in sympathetic control of pacemaking.

描述（由申请人提供）：心脏的每一次节拍始于Sinotrial节点中专门的起搏器细胞的自发性去极化。交感神经系统主要是通过从神经支配窦节点的神经中释放去甲肾上腺素来提高心率。在窦性心肌细胞中，交感性战斗或飞行反应的这一方面要求对脱甲肾上腺素做出反应的2个肾上腺素能受体（2AR）与共同控制动作电位的时机和形状的离子通道。该项目的长期目标是了解产生和调节窦性肌细胞起搏器活性的分子机械。该提案中概述的实验集中在2ARS和超极化激活，环状核苷酸敏感（HCN或Pacemaker）离子通道之间的某些方面。 HCN通道被2ARS激活，被认为对于设定静息心率和介导2种激动剂的阳性表年度效应至关重要。然而，对HCN通道参与起搏的生物物理机制以及HCN通道和2个肾上腺素能受体之间的功能和物理关系知之甚少。在该项目中要测试的工作假设是，HCN通道产生的泄漏电流对于窦心肌细胞中的起搏器活动至关重要，并且对起搏器的交感神经调节需要包含2ARS和HCN通道的大分子信号传导复合物。这些问题将使用表达的HCN通道，急性隔离的鼠节肌细胞和培养的正弦肌细胞来解决。要采用的原理技术是斑块夹电生理学，共聚焦免疫荧光显微镜和免疫亲和力色谱。有三个具体的目的：（1）了解舒张期HCN通道活性的生物物理机制，（2）描述控制2ARS和HCN通道之间的功能关系，这些功能关系控制了辛迪尔肌细胞中的发射速率，（3）以确定参与PACEMEMEMEMEMECEMEMECTECTECTIC CONTRATIC CONTARTATE CONTATE PACETATE的蛋白质相互作用的亚细胞定位和物理相互作用。