Receptors, sparks and waves in a fire-diffuse-fire framework for calcium release

Calcium ions are an important second messenger in living cells. Indeed calcium signals in the form of waves have been the subject of much recent experimental interest. It is now well established that these waves are composed of elementary stochastic release events (calcium puffs or sparks) from sp...

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Main Authors: Coombes, Stephen, Hinch, Robert, Timofeeva, Yulia
Format: Article
Published: 2004
Subjects:
Online Access:https://eprints.nottingham.ac.uk/107/
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author Coombes, Stephen
Hinch, Robert
Timofeeva, Yulia
author_facet Coombes, Stephen
Hinch, Robert
Timofeeva, Yulia
author_sort Coombes, Stephen
building Nottingham Research Data Repository
collection Online Access
description Calcium ions are an important second messenger in living cells. Indeed calcium signals in the form of waves have been the subject of much recent experimental interest. It is now well established that these waves are composed of elementary stochastic release events (calcium puffs or sparks) from spatially localised calcium stores. The aim of this paper is to analyse how the stochastic nature of individual receptors within these stores combines to create stochastic behaviour on long timescales that may ultimately lead to waves of activity in a spatially extended cell model. Techniques from asymptotic analysis and stochastic phase-plane analysis are used to show that a large cluster of receptor channels leads to a release probability with a sigmoidal dependence on calcium density. This release probability is incorporated into a computationally inexpensive model of calcium release based upon a stochastic generalization of the Fire-Diffuse-Fire (FDF) threshold model. Numerical simulations of the model in one and two dimensions (with stores arranged on both regular and disordered lattices) illustrate that stochastic calcium release leads to the spontaneous production of calcium sparks that may merge to form saltatory waves. Illustrations of spreading circular waves, spirals and more irregular waves are presented. Furthermore, receptor noise is shown to generate a form of array enhanced coherence resonance whereby all calcium stores release periodically and simultaneously.
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spelling nottingham-1072020-05-04T20:31:13Z https://eprints.nottingham.ac.uk/107/ Receptors, sparks and waves in a fire-diffuse-fire framework for calcium release Coombes, Stephen Hinch, Robert Timofeeva, Yulia Calcium ions are an important second messenger in living cells. Indeed calcium signals in the form of waves have been the subject of much recent experimental interest. It is now well established that these waves are composed of elementary stochastic release events (calcium puffs or sparks) from spatially localised calcium stores. The aim of this paper is to analyse how the stochastic nature of individual receptors within these stores combines to create stochastic behaviour on long timescales that may ultimately lead to waves of activity in a spatially extended cell model. Techniques from asymptotic analysis and stochastic phase-plane analysis are used to show that a large cluster of receptor channels leads to a release probability with a sigmoidal dependence on calcium density. This release probability is incorporated into a computationally inexpensive model of calcium release based upon a stochastic generalization of the Fire-Diffuse-Fire (FDF) threshold model. Numerical simulations of the model in one and two dimensions (with stores arranged on both regular and disordered lattices) illustrate that stochastic calcium release leads to the spontaneous production of calcium sparks that may merge to form saltatory waves. Illustrations of spreading circular waves, spirals and more irregular waves are presented. Furthermore, receptor noise is shown to generate a form of array enhanced coherence resonance whereby all calcium stores release periodically and simultaneously. 2004-02 Article PeerReviewed Coombes, Stephen, Hinch, Robert and Timofeeva, Yulia (2004) Receptors, sparks and waves in a fire-diffuse-fire framework for calcium release. calcium sparks ryanodine receptors intracellular signalling fire-diffuse-fire stochastic transitions calcium waves
spellingShingle calcium sparks
ryanodine receptors
intracellular signalling
fire-diffuse-fire
stochastic transitions
calcium waves
Coombes, Stephen
Hinch, Robert
Timofeeva, Yulia
Receptors, sparks and waves in a fire-diffuse-fire framework for calcium release
title Receptors, sparks and waves in a fire-diffuse-fire framework for calcium release
title_full Receptors, sparks and waves in a fire-diffuse-fire framework for calcium release
title_fullStr Receptors, sparks and waves in a fire-diffuse-fire framework for calcium release
title_full_unstemmed Receptors, sparks and waves in a fire-diffuse-fire framework for calcium release
title_short Receptors, sparks and waves in a fire-diffuse-fire framework for calcium release
title_sort receptors, sparks and waves in a fire-diffuse-fire framework for calcium release
topic calcium sparks
ryanodine receptors
intracellular signalling
fire-diffuse-fire
stochastic transitions
calcium waves
url https://eprints.nottingham.ac.uk/107/