Reassessment of mechanical restitution in guinea pig cardiomyocytes through refined computational modelling

Abstract Mechanical restitution (MR) represents the time recovery of the heart muscle’s ability to contract. Despite intensive research, some aspects of MR remain unclear. To describe MR in guinea pig cardiac muscle, we modified our published mathematical model of guinea pig ventricular cardiomyocyt...

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Main Authors: Michal Pásek, Marie Nováková
Format: Article
Language:English
Published: Nature Portfolio 2025-08-01
Series:Scientific Reports
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Online Access:https://doi.org/10.1038/s41598-025-14815-1
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author Michal Pásek
Marie Nováková
author_facet Michal Pásek
Marie Nováková
author_sort Michal Pásek
collection DOAJ
description Abstract Mechanical restitution (MR) represents the time recovery of the heart muscle’s ability to contract. Despite intensive research, some aspects of MR remain unclear. To describe MR in guinea pig cardiac muscle, we modified our published mathematical model of guinea pig ventricular cardiomyocyte and supplemented it with a description of cellular contraction. To achieve the best agreement between the model simulations and available experimental data, some model parameters were optimised. The model enables the simulation of the experimentally observed fast onset of recovery of action potential duration, L-type Ca2+ current amplitude, and isometric force. The performed simulations and analyses of model data showed that the high time constant of voltage-dependent inactivation of L-type Ca2+ channels used in previously published models (~ 600 ms at resting voltage) is not consistent with the initial steep rise of the MR curve in guinea pig cardiomyocytes. It also suggests that the adaptation rate of ryanodine receptors, which was set differently in the previous models, is fast (~ 100 s− 1). Finally, analysis of the effect of a 50% reduction in membrane currents on MR revealed a marked dependence on stimulation frequency. At 1 Hz, only the reduction of I NaCa and I NaK significantly affected the MR course.
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spelling doaj-art-2a40aa7af6c640ceaa84f111517f5e902025-08-20T03:46:08ZengNature PortfolioScientific Reports2045-23222025-08-0115111310.1038/s41598-025-14815-1Reassessment of mechanical restitution in guinea pig cardiomyocytes through refined computational modellingMichal Pásek0Marie Nováková1Department of Physiology, Faculty of Medicine, Masaryk University BrnoDepartment of Physiology, Faculty of Medicine, Masaryk University BrnoAbstract Mechanical restitution (MR) represents the time recovery of the heart muscle’s ability to contract. Despite intensive research, some aspects of MR remain unclear. To describe MR in guinea pig cardiac muscle, we modified our published mathematical model of guinea pig ventricular cardiomyocyte and supplemented it with a description of cellular contraction. To achieve the best agreement between the model simulations and available experimental data, some model parameters were optimised. The model enables the simulation of the experimentally observed fast onset of recovery of action potential duration, L-type Ca2+ current amplitude, and isometric force. The performed simulations and analyses of model data showed that the high time constant of voltage-dependent inactivation of L-type Ca2+ channels used in previously published models (~ 600 ms at resting voltage) is not consistent with the initial steep rise of the MR curve in guinea pig cardiomyocytes. It also suggests that the adaptation rate of ryanodine receptors, which was set differently in the previous models, is fast (~ 100 s− 1). Finally, analysis of the effect of a 50% reduction in membrane currents on MR revealed a marked dependence on stimulation frequency. At 1 Hz, only the reduction of I NaCa and I NaK significantly affected the MR course.https://doi.org/10.1038/s41598-025-14815-1Mechanical restitutionGuinea pig cardiomyocyteMathematical modelCalcium currentRyanodine receptor
spellingShingle Michal Pásek
Marie Nováková
Reassessment of mechanical restitution in guinea pig cardiomyocytes through refined computational modelling
Scientific Reports
Mechanical restitution
Guinea pig cardiomyocyte
Mathematical model
Calcium current
Ryanodine receptor
title Reassessment of mechanical restitution in guinea pig cardiomyocytes through refined computational modelling
title_full Reassessment of mechanical restitution in guinea pig cardiomyocytes through refined computational modelling
title_fullStr Reassessment of mechanical restitution in guinea pig cardiomyocytes through refined computational modelling
title_full_unstemmed Reassessment of mechanical restitution in guinea pig cardiomyocytes through refined computational modelling
title_short Reassessment of mechanical restitution in guinea pig cardiomyocytes through refined computational modelling
title_sort reassessment of mechanical restitution in guinea pig cardiomyocytes through refined computational modelling
topic Mechanical restitution
Guinea pig cardiomyocyte
Mathematical model
Calcium current
Ryanodine receptor
url https://doi.org/10.1038/s41598-025-14815-1
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