SASAKI Daisuke
   Department   Research Institutes and Facilities, Research Institutes and Facilities
   Position   Assistant Professor (Fixed Term)
Article types Original article
Language English
Peer review Peer reviewed
Title Auto-oscillations of skinned myocardium correlating with heartbeat.
Journal Formal name：Journal of muscle research and cell motility
Abbreviation：J Muscle Res Cell Motil
ISSN code：01424319/01424319
Domestic / ForeginForegin
Volume, Issue, Page 26(2-3),pp.93-101
Author and coauthor Sasaki Daisuke, Fujita Hideaki, Fukuda Norio, Kurihara Satoshi, Ishiwata Shin'ichi
Publication date 2005
Summary Skinned myocardium (or myofibrils) exhibits auto-oscillations of sarcomere length and developed force called SPOC (SPontaneousOscillatoryContraction) under partial activation conditions. In SPOC, each sarcomere repeats the cycle of slow shortening and rapid lengthening, and the lengthening phase propagates sequentially to the adjacent sarcomeres in waves (SPOC wave). In this study, we analyzed the sarcomeric oscillation in SPOC in skinned myocardium of various animal species (rat, rabbit, dog, pig, and cow) with different heart rates. The period of oscillation, the sarcomere shortening velocity, and the velocity of SPOC wave, strongly correlated with the resting heart rate of the animal species. The shortening velocity in particular was proportional to the resting heart rate. We then examined the motile activity of each cardiac myosin by an in vitro motility assay. The sliding velocity of actin filaments, which is an index of the motile activity of myosin, also correlated with the resting heart rate but the relationship was not proportional. As a result, the ratio of sarcomere shortening velocity in SPOC to the sliding velocity of actin filaments was not constant but became higher with a higher heart rate. This suggests that the sarcomere shortening velocity in SPOC is modulated by some additional factors besides the motile activity of myosin, resulting in the proportional relationship between the shortening velocity of the sarcomere and the resting heart rate.
DOI 10.1007/s10974-005-0249-2
PMID 15999228