フルテキストURL K0005571_orher1.pdf K0005571_summary2.pdf
著者 Iribe, Gentaro| Kaneko, Toshiyuki| Yamaguchi, Yohei| Naruse, Keiji|
抄録 The previously reported pressure-volume (PV) relationship in frog hearts shows that end-systolic PV relation (ESPVR) is load dependent, whereas ESPVR in canine hearts is load independent. To study intrinsic cardiac mechanics in detail, it is desirable to study mechanics in a single isolated cardiomyocyte that is free from interstitial connective tissue. Previous single cell mechanics studies used a pair of carbon fibers (CF) attached to the upper surface of opposite cell ends to stretch cells. These studies showed that end-systolic force-length (FL) relation (ESFLR) is load independent. However, the range of applicable mechanical load using the conventional technique is limited because of weak cell-CF attachment. Therefore, the behavior of ESFLR in single cells under physiologically possible conditions of greater load is not yet well known. To cover wider loading range, we contrived a new method to hold cell-ends more firmly using two pairs of CF attached to both upper and bottom surfaces of cells. The new method allowed stretching cells to 2.2 μm or more in end-diastolic sarcomere length. ESFLR virtually behaves in a load independent manner only with end-diastolic sarcomere length less than 1.95 μm. It exhibited clear load dependency with higher preload, especially with low afterload conditions. Instantaneous cellular elastance curves showed that decreasing afterload enhanced relaxation and slowed time to peak elastance, as previously reported. A simulation study of a mathematical model with detailed description of thin filament activation suggested that velocity dependent thin filament inactivation is crucial for the observed load dependent behaviors and previously reported afterload dependent change in Ca(2+) transient shape.
キーワード Cell mechanics Mechano-electric coupling Modeling Shortening deactivation
備考 学位審査副論文
発行日 2014-08
出版物タイトル Progress in Biophysics and Molecular Biology
115巻
2-3号
出版者 Pergamon Press
開始ページ 103
終了ページ 114
ISSN 0079-6107
NCID AA00789136
資料タイプ 学術雑誌論文
言語 English
OAI-PMH Set 岡山大学
著作権者 https://creativecommons.org/licenses/by-nc-nd/4.0/deed.ja
論文のバージョン author
PubMed ID 24976617
DOI 10.1016/j.pbiomolbio.2014.06.005
Web of Sience KeyUT 000344424700005
関連URL https://doi.org/10.1016/j.pbiomolbio.2014.06.005 http://ousar.lib.okayama-u.ac.jp/55243