SARCOPLASMIC RETICULUM CA2+ RELEASE IN HEART

心脏肌浆网 CA2 释放

• 批准号: 3355243
• 负责人: GERHARD W MEISSNER
• 金额: $ 12.47万
• 依托单位: UNIV OF NORTH CAROLINA CHAPEL HILL
• 依托单位国家: 美国
• 财政年份: 1987
• 资助国家: 美国
• 起止时间: 1987-09-30 至 1990-09-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3355243
• 关键词: adenine nucleotides; calcium channel; calcium metabolism; calmodulin; dogs; heart pharmacology; ligands; membrane activity; membrane channels; membrane model; myocardial ischemia /hypoxia; myocardium; sarcoplasmic reticulum

The objective of this proposal is to determine the functional properties of a ligand-gated "Ca2+ release" channel in cardiac sarcoplasmic reticulum (SR). In isolated sarcoplasmic reticulum membrane fractions, this channel mediates Ca2+ fluxes with rates sufficiently rapid to suggest a central role in the process of excitation-contraction coupling. Sedimentation and equilibrium centrifugation techniques will be used to isolate "Ca2+ release" vesicles containing the cardiac SR Ca2+ release channel, "control" SR vesicles lacking the Ca2+ release channel, as well as junctional complexes composed of SR and surface membranes. Regulation of the cardiac SR Ca2+ release channel by Ca2+, Mg2+, H+, adenine nucleotides, calmodulin, and other factors will be determined on a time scale of milliseconds to minutes, using radioisotope flux -rapid quench and filtration techniques. In addition, cardiac SR Ca2+ release channels will be incorporated into planar lipid bilayers so that single channel conductance, ion selectivity and voltage-dependence, as well as the kinetics of channel activation and inactivation can be investigated. Surface membrane depolarization-induced Ca2+ release will be studied by measuring, in the presence and absence of transient membrane potentials, Ca+2 efflux from the SR compartment of surface membrane/SR junctional complexes. The effects of drugs will be tested to suggest ways to identifying and purifying the Ca2+ release channel components as well as modifying Ca2+ release in vivo. The Ca2+ release properties of membrane fractions isolated from ischemic hearts will be analyzed in order to detect a possible defect in SR Ca2+ release that may be related to or may potentiate loss of function during heart failure.

该建议的目的是确定功能 心脏配体门控的“ Ca2+释放”通道的特性 肌质网（SR）。 在孤立的肌质网中 膜分数，该通道以速率介导Ca2+通量 足够迅速地暗示了在此过程中的核心作用 激发反应耦合。 沉积和平衡 离心技术将用于隔离“ Ca2+释放” 包含心脏SR Ca2+释放通道的囊泡“控制” 缺乏Ca2+释放通道的SR囊泡以及连接 由SR和表面膜组成的复合物。 规定 Ca2+，Mg2+，H+，CA2+发行通道的心脏SR CA2+释放通道 腺嘌呤核苷酸，钙调蛋白和其他因素将是 使用毫秒到几分钟的时间尺度确定 放射性同位素通量 - rapid淬灭和过滤技术。 在 此外，将合并心脏SR CA2+释放通道 进入平面脂质双层，使单个通道电导离子离子 选择性和电压依赖性以及动力学 可以研究通道激活和灭活。 表面 膜去极化引起的Ca2+释放将通过 在存在和不存在瞬时膜的情况下测量 电势，Ca+2从SR隔室的Ca+2外排 膜/SR连接络合物。 药物的影响将是 经过测试以建议识别和净化Ca2+的方法 释放通道组件以及修改Ca2+释放 体内。 分离的膜分数的Ca2+释放特性 从缺血性心脏中进行分析，以检测 可能与或可能有关的SR Ca2+释放中可能的缺陷 心力衰竭期间功能的功能丧失。