ArticleThe Journal of general physiology2002
Comparison of simulated and measured calcium sparks in intact skeletal muscle fibers of the frog.
Article in The Journal of general physiology, 2002. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 28 papers.
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Who cites it
28 citing papers in PubMed.
- Thirty years of CaBiophysics reports · 2024Article
- Nernst-Planck-Gaussian finite element modelling of CaFrontiers in physiology · 2024Article
- Finite element analysis predicts CaScientific reports · 2021Article
- Voltage sensing mechanism in skeletal muscle excitation-contraction coupling: coming of age or midlife crisis?Skeletal muscle · 2018Review
- Doublet stimulation increases CaThe Journal of general physiology · 2017Article
- Modeling CaFrontiers in physiology · 2016Article
- Intracellular calcium movements during relaxation and recovery of superfast muscle fibers of the toadfish swimbladder.The Journal of general physiology · 2014Article
- Comparison of myoplasmic calcium movements during excitation-contraction coupling in frog twitch and mouse fast-twitch muscle fibers.The Journal of general physiology · 2013Article
- Developmental profile of localized spontaneous Ca(2+) release events in the dendrites of rat hippocampal pyramidal neurons.Cell calcium · 2012Article
- Intracellular calcium movements during excitation-contraction coupling in mammalian slow-twitch and fast-twitch muscle fibers.The Journal of general physiology · 2012Review
- Synthetic localized calcium transients directly probe signalling mechanisms in skeletal muscle.The Journal of physiology · 2012Article
- Properties of Ca2+ sparks revealed by four-dimensional confocal imaging of cardiac muscle.The Journal of general physiology · 2012Article
- Calcium indicators and calcium signalling in skeletal muscle fibres during excitation-contraction coupling.Progress in biophysics and molecular biology · 2011Review
- Measurement of calcium dissociation rates from troponin C in rigor skeletal myofibrils.Frontiers in physiology · 2011Article
- Monitoring the structural behavior of troponin and myoplasmic free Ca2+ concentration during twitch of frog skeletal muscle.Biophysical journal · 2010Article
- Article
- Models and mechanistic insight.The Journal of general physiology · 2008Article
- Sparks and embers of skeletal muscle: the exciting events of contractile activation.Pflugers Archiv : European journal of physiology · 2007Review
- Role of calsequestrin evaluated from changes in free and total calcium concentrations in the sarcoplasmic reticulum of frog cut skeletal muscle fibres.The Journal of physiology · 2007Article
- Effects of tetracaine on voltage-activated calcium sparks in frog intact skeletal muscle fibers.The Journal of general physiology · 2006Article
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Authors and funding
3 authors.
Funding
Abstract
Calcium sparks in frog intact skeletal muscle fibers were modeled as stereotypical events that arise from a constant efflux of Ca(2+) from a point source for a fixed period of time (e.g., 2.5 pA of Ca(2+) current for 4.6 ms; 18 degrees C). The model calculates the local changes in the concentrations of free Ca(2+) and of Ca(2+) bound to the major intrinsic myoplasmic Ca(2+) buffers (troponin, ATP, parvalbumin, and the SR Ca(2+) pump) and to the Ca(2+) indicator (fluo-3). A distinctive feature of the model is the inclusion of a binding reaction between fluo-3 and myoplasmic proteins, a process that strongly affects fluo-3's Ca(2+)-reaction kinetics, its apparent diffusion constant, and hence the morphology of sparks. DeltaF/F (the change in fluo-3's fluorescence divided by its resting fluorescence) was estimated from the calculated changes in fluo-3 convolved with the microscope point-spread function. To facilitate comparisons with measured sparks, noise and other sources of variability were included in a random repetitive fashion to generate a large number of simulated sparks that could be analyzed in the same way as the measured sparks. In the initial simulations, the binding of Ca(2+) to the two regulatory sites on troponin was assumed to follow identical and independent binding reactions. These simulations failed to accurately predict the falling phase of the measured sparks. A second set of simulations, which incorporated the idea of positive cooperativity in the binding of Ca(2+) to troponin, produced reasonable agreement with the measurements. Under the assumption that the single channel Ca(2+) current of a ryanodine receptor (RYR) is 0.5-2 pA, the results suggest that 1-5 active RYRs generate an average Ca(2+) spark in a frog intact muscle fiber.
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