Szekely, David, Brennan, Sarah C. ![]() |
Abstract
Oscillations of the intracellular concentration of Ca2+ in cultured HEK-293 cells, which heterologously expressed the calcium-sensing receptor, were recorded with the fluorophore Fura-2 using fluorescence microscopy. HEK-293 cells are extremely sensitive to small perturbations in extracellular calcium concentrations. Resting cells were attached to cover slips and perifused with saline solution containing physiologically relevant extracellular Ca2+ concentrations in the range 0.5–5 mM. Acquired digitized images of the cells showed oscillatory fluctuations in the intracellular Ca2+ concentration over the time course, and were processed as a function of the change in Fura-2 excitation ratio and frequency at 12–37°C. Newly developed data processing techniques with wavelet analysis were used to estimate the frequency at which the rectified sinusoidal oscillations occurred; we estimated ~4 min−1 under normal conditions. Temperature variations revealed an Arrhenius relationship in oscillation frequency. A critical Ca2+ concentration of ~2 mM was estimated, below which oscillations did not occur. These data were used to develop a kinetic model of the system that was simulated using Mathematica; kinetic parameter values were adjusted to match the experimentally observed oscillations of intracellular Ca2+ concentration as a function of extracellular Ca2+ concentration, and temperature; and from these, limit cycles were obtained and control coefficients were estimated for all parameters.
Item Type: | Article |
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Date Type: | Publication |
Status: | Published |
Schools: | Biosciences |
Publisher: | Springer |
ISSN: | 0175-7571 |
Last Modified: | 27 Oct 2022 09:26 |
URI: | https://orca.cardiff.ac.uk/id/eprint/65843 |
Citation Data
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