A model-independent algorithm to derive Ca2+ fluxes underlying local cytosolic Ca2+ transients

Local intracellular Ca(2+) signals result from Ca(2+) flux into the cytosol through individual channels or clusters of channels. To gain a mechanistic understanding of these events we need to know the magnitude and spatial distribution of the underlying Ca(2+) flux. However, this is difficult to inf...

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Bibliographic Details
Published in:Biophysical journal 2005-04, Vol.88 (4), p.2403-2421
Main Authors: Ventura, Alejandra C, Bruno, Luciana, Demuro, Angelo, Parker, Ian, Dawson, Silvina Ponce
Format: Article
Language:English
Subjects:
Algorithms
Animals
Biophysical Phenomena
Biophysical Theory and Modeling
Biophysics
Buffers
Calcium - chemistry
Calcium - metabolism
Calcium Channels - metabolism
Calcium Signaling
Cytosol - metabolism
Fluorescent Dyes - pharmacology
Ions
Kinetics
Microscopy, Fluorescence
Models, Theoretical
Oocytes - metabolism
Protein Binding
Reproducibility of Results
Time Factors
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Summary:Local intracellular Ca(2+) signals result from Ca(2+) flux into the cytosol through individual channels or clusters of channels. To gain a mechanistic understanding of these events we need to know the magnitude and spatial distribution of the underlying Ca(2+) flux. However, this is difficult to infer from fluorescence Ca(2+) images because the distribution of Ca(2+)-bound dye is affected by poorly characterized processes including diffusion of Ca(2+) ions, their binding to mobile and immobile buffers, and sequestration by Ca(2+) pumps. Several methods have previously been proposed to derive Ca(2+) flux from fluorescence images, but all require explicit knowledge or assumptions regarding these processes. We now present a novel algorithm that requires few assumptions and is largely model-independent. By testing the algorithm with both numerically generated image data and experimental images of sparklets resulting from Ca(2+) flux through individual voltage-gated channels, we show that it satisfactorily reconstructs the magnitude and time course of the underlying Ca(2+) currents.
ISSN:0006-3495
1542-0086
DOI:10.1529/biophysj.104.045260