title: Model simulation of the SPOC wave in a bundle of striated myofibrils.
abstract: SPOC (spontaneous oscillatory contraction) is a phenomenon observed in striated muscle under intermediate activation conditions. Recently, we constructed a theoretical model of SPOC for a sarcomere,a unit sarcomere model, which explains the behavior of SPOC at each sarcomere level. We also constructeda single myofibril model, which visco-elastically connects the unit model in series, and explains the behaviors of SPOC at the myofibril level. In the present study, to understand the SPOC properties in a bundle of myofibrils, we extended the single myofibril model to a two-dimensional (2D) model and a three-dimensional (3D) model, in which myofibrils were elastically connected side-by-side through cross-linkers between the Z-lines and M-lines. These 2D and 3D myofibril models could reproduce various patterns of SPOC waves experimentally observed in a 2D sheet and a 3D bundle of myofibrils only by choosing different values of elastic constants of the cross-linkers and the external spring. The results of these 2D and 3D myofibril models provide insight into the SPOC properties of the higher-ordered assembly of myofibrils.
authors.affiliation: Department of Physics, Faculty of Science and Engineering, Waseda University, Tokyo 169-8555, Japan.
authors.forename: Koutaro
authors.initials: K
authors.lastname: Nakagome
authors.affiliation: Research Institute for Electronic Science (RIES), Hokkaido University, Sapporo, Hokkaido 001-0020, Japan.
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Sato
authors.affiliation: Department of Physics, Faculty of Science, The University of Tokyo, Tokyo 113-8654, Japan.
authors.forename: Seine A
authors.initials: SA
authors.lastname: Shintani
authors.affiliation: Department of Physics, Faculty of Science and Engineering, Waseda University, Tokyo 169-8555, Japan.
authors.forename: Shin'ichi
authors.initials: S
authors.lastname: Ishiwata
keywords: auto-oscillation; coupled oscillators; muscle contraction; spontaneous oscillatory contraction; striated muscle