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.

该提案的目的是确定功能 心脏配体门控“Ca2+释放”通道的特性 肌浆网（SR）。 在孤立的肌浆网中 膜部分，该通道以速率介导 Ca2+ 通量 足够快地表明在这一过程中发挥着核心作用 兴奋-收缩耦合。 沉淀与平衡 离心技术将用于分离“Ca2+释放” 含有心脏 SR Ca2+ 释放通道的囊泡，“对照” SR 囊泡缺乏 Ca2+ 释放通道以及连接 由SR和表面膜组成的复合物。 规定 心脏 SR Ca2+ 释放通道的 Ca2+、Mg2+、H+、 腺嘌呤核苷酸、钙调蛋白和其他因子 在毫秒到分钟的时间尺度上确定，使用 放射性同位素通量-快速淬灭和过滤技术。 在 此外，心脏 SR Ca2+ 释放通道将被纳入 进入平面脂质双层，使单通道电导、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失活。 表面 膜去极化诱导的 Ca2+ 释放将通过以下方式进行研究 在存在和不存在瞬态膜的情况下进行测量 电位，Ca+2 从表面 SR 室流出 膜/SR 连接复合物。 药物的作用将会是 经过测试，提出了识别和纯化 Ca2+ 的方法 释放通道成分以及修改Ca2+释放 体内。 分离的膜组分的 Ca2+ 释放特性 将分析来自缺血心脏的样本，以检测 SR Ca2+ 释放中可能存在的缺陷可能与 加剧心力衰竭期间的功能丧失。