TIME-RESOLVED X-RAY DIFFRACTION OF CARDIAC MUSCLE

心肌的时间分辨 X 射线衍射

• 批准号: 8361264
• 负责人: Pieter P. de TOMBE
• 金额: $ 2.97万
• 依托单位: ILLINOIS INSTITUTE OF TECHNOLOGY
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-01-01 至 2011-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8361264
• 关键词: Adult; Affect; Biophysics; Cardiac; Cardiac Volume; Funding; Grant; Head; Heart; Ions; Length; Microfilaments; Muscle; Myocardium; Myosin ATPase; National Center for Research Resources; Operating System; Pattern; Positioning Attribute; Principal Investigator; Production; Radial; Rattus; Relative (related person); Research; Research Infrastructure; Resources; Sarcomeres; Source; Starling (law); Thick Filament; Thin Filament; Time; United States National Institutes of Health; Vertebral column; X ray diffraction analysis; X-Ray Diffraction; base; cost; interest; two-dimensional

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. The so-called "Frank Starling Law of the Heart" describes the relationship between end-diastolic volume and cardiac ejection volume that is the major regulatory system operating on a beat to beat basis in the adult heart. The main cellular mechanism that underlies this phenomenon is an increase in the responsiveness of cardiac myofilaments to activating Ca2+ ions at longer sarcomere lengths. The fundamental mechanism responsible for this increase in responsiveness has been elusive despite considerable experimental scrutiny by various research groups. This project we aim to determine the structural mechanisms behind this phenomenon. We obtain two-dimensional x-ray diffraction patterns from electrically stimulated, continuously twitching, rat cardiac muscle . We are particularly interested in structural changes that occur with changes in muscle length under diastolic conditions that can be related to subsequent force production. We examine the relative position of the heads to the thin filaments (via the I11/I10 equatorial intensity ratio), the radial extent of the heads from the center of the thick filament backbones (from the myosin layer lines), strain in the thick filament backbones (from the spacing of the m6 meridional reflection), and the orientation of the myosin heads around the normal to the thick filament long axis (m3 reflection intensity). Any of these factors could be expected to affect force production if they change as a function of sarcomere length.

该副本是利用资源的众多研究子项目之一 由NIH/NCRR资助的中心赠款提供。对该子弹的主要支持 而且，副投影的主要研究员可能是其他来源提供的 包括其他NIH来源。 列出的总费用可能 代表subproject使用的中心基础架构的估计量， NCRR赠款不直接向子弹或副本人员提供的直接资金。 所谓的“心脏弗兰克·史塔林法”描述了末期舒适量和心脏射血量之间的关系，这是在成人心脏中以节奏打败基础的主要监管系统。构成这种现象的主要细胞机制是心肌丝丝对在较长的肌节长度上激活Ca2+离子的反应性的提高。尽管各个研究小组进行了相当多的实验审查，但导致这种响应能力增加的基本机制仍然难以捉摸。我们旨在确定这种现象背后的结构机制。 我们从电刺激的，不断抽动的大鼠心肌肌肉中获得二维X射线衍射图。我们对在舒张期可能与随后的力产生有关的肌肉长度变化发生的结构变化特别感兴趣。 We examine the relative position of the heads to the thin filaments (via the I11/I10 equatorial intensity ratio), the radial extent of the heads from the center of the thick filament backbones (from the myosin layer lines), strain in the thick filament backbones (from the spacing of the m6 meridional reflection), and the orientation of the myosin heads around the normal to the thick filament long axis (m3 reflection 强度）。如果这些因素随着肌节长度的函数而变化，则可以预期它们会影响力的产生。