| Project/Area Number |
15300175
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Biomedical engineering/Biological material science
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| Research Institution | Kawasaki Medical School |
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Principal Investigator |
TSUJIOKA Katsuhiko Kawasaki Medical School, Department of Physiology, Professor, 医学部, 教授 (30163801)
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| Co-Investigator(Kenkyū-buntansha) |
OKUYAMA Hiroshi Kawasaki Medical School, Department of Physiology, Lecturer, 医学部, 講師 (30133333)
MIYASAKA Takehiro Okayama University, Graduate School of Medicine and Dentistry, Assistant Professor, 大学院・医歯学総合研究科・医学部, 助手 (60308195)
YAGI Naoto Japan Synchrotron Radiation Research Institute, Principal Investigator, 主席研究員(研究職) (80133940)
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| Project Period (FY) |
2003 – 2005
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| Project Status |
Completed (Fiscal Year 2005)
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| Budget Amount *help |
¥16,200,000 (Direct Cost: ¥16,200,000)
Fiscal Year 2005: ¥5,000,000 (Direct Cost: ¥5,000,000)
Fiscal Year 2004: ¥5,400,000 (Direct Cost: ¥5,400,000)
Fiscal Year 2003: ¥5,800,000 (Direct Cost: ¥5,800,000)
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| Keywords | synchrotron radiation x-ray / cardiac muscle / actin / myosin head / crossbridge / x-ray diffraction / laser diffraction / srcomere / レーザ回折 |
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| Research Abstract |
The purpose of this project is to analyze the molecular interaction between actin and myosin in isolated cardiac muscle and whole heart with time- resolved way in one cardiac cycle.
We assembled the short angle diffraction apparatus with x-ray energy 12.4keV and wave length 1 A at BL45XU beam line in Spring-8 (Super Photon Ring 8GeV). We measured x-ray diffraction pattern by using x-ray image intensifier and cooled CCD. For the measurement of diffraction pattern from the left ventricle we used BL40XU, which has higher energy than BL45XU. In this case the camera length was 3m and x-ray energy was 16keV. We controlled the x-ray energy to the suitable strength with changing the width of front-end slit. We measured the sarcomere length by laser diffraction pattern and compared it with lateral diffraction pattern by x-ray, and thus analyze the three-dimensional dynamics between molecular and cellular level.
We got the equatorial diffraction from isolated and perfused papillary muscle from rig
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ht ventricle of rat. From the ratio between (1,0)/(1,1) diffraction the mass transfer from the myosin molecule to actin molecule, which is the index of crossbridge formation, was measured. We analyzed the change of molecular interaction between actin and myosin with the change of sarcomere length and afterload in isometric and isotonic contraction. In addition we analyzed the x-ray diffraction pattern from left ventricular wall in isolated Langendorff-perfusion heart.
As the mass transfer from myosin molecular to actin increased with cardiac muscle length in isometric contraction, we concluded the amount of crossbridge formation is the molecular basis of the Starling mechanism of the heart. In isotonic contraction the developed force also increased with the amount of crossbridge formation. However, the amount of mass-transfer from the myosin molecular to actin in small afterloaded contraction was interestingly smaller than that at the same developed force in isometric contraction. The developed pressure in isovolumically contracting left ventricle was in accordance with the mass-transfer, indicating the molecular basis of the Staring mechanism of the heart in whole heart. The diffraction pattern from the left ventricular wall changed with regular manner depending on x-ray irradiation portion at subepicardium, mid wall and subendocardium. We concluded that the change of the three-dimensional molecular structure at the different portion of the left ventricular free wall could be estimated in time resolved manner in isovolumically contracting isolated and perfused heart. Less
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