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Receptors, sparks and waves in a fire-diffuse-fire framework for calcium release
S Coombes1, R Hinch, Y Timofeeva
1Centre for Mathematical Medicine, School of Mathematical Sciences, University of Nottingham, Nottingham, NG7 2RD, UK. stephen.coombes@nottingham.ac.uk
Progress in Biophysics and Molecular Biology
|May 15, 2004
Summary
Cellular calcium ions act as messengers, forming waves from tiny release events. This study shows how random receptor behavior in calcium stores generates these signals, leading to wave formation and synchronized cellular activity.
Area of Science:
- Cell Biology
- Biophysics
- Computational Biology
Background:
- Calcium ions are crucial intracellular second messengers.
- Calcium signals often propagate as waves, originating from localized release events.
- Understanding the stochastic nature of these events is key to explaining wave formation.
Purpose of the Study:
- To analyze how stochastic receptor behavior in calcium stores generates macroscopic calcium waves.
- To develop a computationally efficient model for calcium release dynamics.
- To investigate wave propagation patterns in spatially extended cell models.
Main Methods:
- Asymptotic analysis and stochastic phase-plane analysis were employed.
- A sigmoidal dependence of release probability on calcium density was derived.
- A stochastic generalization of the fire-diffuse-fire (FDF) model was utilized.
- Numerical simulations in 1D and 2D on regular and disordered lattices were performed.
Main Results:
- Stochastic calcium release spontaneously produces calcium sparks.
- These sparks can merge to form saltatory waves, including circular and spiral patterns.
- Receptor noise induces array-enhanced coherence resonance, synchronizing calcium store release.
Conclusions:
- The stochastic nature of individual calcium release channels drives macroscopic wave phenomena.
- The developed FDF model provides an efficient method for simulating calcium dynamics.
- Synchronized calcium release through coherence resonance is a significant emergent property.