title: Modelling and measuring electromechanical coupling in the rat heart.
abstract: Tension-dependent binding of Ca(2+) to troponin C in the cardiac myocyte has been shown to play an important role in the regulation of Ca(2+) and the activation of tension development. The significance of this regulatory mechanism is quantified experimentally by the quantity of Ca(2+) released following a rapid change in the muscle length. Using a computational, coupled, electromechanics cell model, we have confirmed that the tension dependence of Ca(2+) binding to troponin C, rather than cross-bridge kinetics or the rate of Ca(2+) uptake by the sarcoplasmic reticulum, determines the quantity of Ca(2+) released following a length step. This cell model has been successfully applied in a continuum model of the papillary muscle to analyse experimental data, suggesting the tension-dependent binding of Ca(2+) to troponin C as the likely pathway through which the effects of localized impaired tension generation alter the Ca(2+) transient. These experimental results are qualitatively reproduced using a three-dimensional coupled electromechanics model. Furthermore, the model predicts that changes in the Ca(2+) transient in the viable myocardium surrounding the impaired region are amplified in the absence of tension-dependent binding of Ca(2+) to troponin C.
authors.affiliation: University Computing Laboratory, University of Oxford, Oxford, UK.
authors.forename: S A
authors.initials: SA
authors.lastname: Niederer
authors.forename: H E D J
authors.initials: HE
authors.lastname: Ter Keurs
authors.forename: N P
authors.initials: NP
authors.lastname: Smith
mesh_terms: D000818:Animals; D020013:Calcium Signaling; D055724:Electrophysiological Phenomena; D006321:Heart / Q000502:physiology*; D008955:Models, Cardiovascular; D009200:Myocardial Contraction / Q000502:physiology; D032383:Myocytes, Cardiac / Q000502:physiology; D010210:Papillary Muscles / Q000502:physiology; D051381:Rats; D012519:Sarcoplasmic Reticulum / Q000378:metabolism; D019209:Troponin C / Q000378:metabolism
chemical_list: D019209:Troponin C