Biomedical Engineering Reference
In-Depth Information
Chapter 7
A Cross-Bridge Model Describing
the Mechanoenergetics of Actomyosin
Interaction
Mari Kalda, Pearu Peterson, Jüri Engelbrecht, and Marko Vendelin
Abstract
In order to study the mechanical contraction and energy consumption by
the cardiomyocytes we further developed an actomyosin model of Vendelin et al.
(Ann. Biomed. Eng. 28:629-640,
2000
). The model is of a self-consistent Huxley-
type and is based on Hill formalism linking the free energy profile of reactions and
mechanical force. In several experimental studies it has been shown that the depen-
dency between oxygen consumption and stress-strain area is linear and is the same
for isometric and shortening contractions. We analyzed the free energy profiles of
actomyosin interaction by changing free energies of intermediate states and acti-
vation of different reactions. The model is able to replicate the linear dependence
between oxygen consumption and stress-strain area together with other important
mechanical properties of a cardiac muscle.
7.1 Introduction
The intracellular environment of heart muscle cells is extensively compartmental-
ized with the several diffusion obstacles possibly separating mitochondria, the main
source of ATP in mammalian heart, from ATPases (Kaasik et al.,
2001
; Vendelin and
Birkedal,
2008
; Sepp et al.,
2010
; Jepihhina et al.,
2011
). The compartmentation of
M. Kalda
M. Vendelin
Laboratory of Systems Biology, Institute of Cybernetics, Tallinn University of Technology,
Akadeemia 21, Tallinn, Estonia
M. Kalda
e-mail:
mari@sysbio.ioc.ee
P. P e t e r s o n
e-mail:
pearu@sysbio.ioc.ee
M. Vendelin
e-mail:
markov@sysbio.ioc.ee
·
P. P e t e r s o n
·
J. Engelbrecht (
)
Centre for Nonlinear Studies, Institute of Cybernetics, Tallinn University of Technology,
Akadeemia 21, Tallinn, Estonia
e-mail:
je@ioc.ee
