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A cooperative model for Ca ++ efflux windowing from cell membranes exposed to electromagnetic radiation
Author(s) -
Thompson C.J.,
Yang Y.S.,
Anderson V.,
Wood A.W.
Publication year - 2000
Publication title -
bioelectromagnetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.435
H-Index - 81
eISSN - 1521-186X
pISSN - 0197-8462
DOI - 10.1002/1521-186x(200009)21:6<455::aid-bem5>3.0.co;2-g
Subject(s) - bistability , membrane , electromagnetic field , power density , efflux , biophysics , coupling (piping) , coupling constant , lattice (music) , chemistry , physics , condensed matter physics , thermodynamics , materials science , power (physics) , quantum mechanics , biology , biochemistry , acoustics , metallurgy
We propose a simplified version of a cooperative lattice membrane model given by Grodsky to explain observed Ca ++ efflux windowing effects from cell membranes exposed to electromagenetic radiation. Assuming that field induced conformational interactions occur only between bistable receptor sites and glycoprotein Ca ++ sites on the surface of the membrane, the model is shown to be equivalent to an Ising model. This model is known to have a phase transition to an ordered state in which a macroscopic number of Ca ++ sites are either occupied or unoccupied. We identify such states with enhanced Ca ++ efflux from cell membranes. By further assuming an averaged signal, sinusoidally varying coupling between receptor and Ca ++ sites and a power‐law dependence of the characteristic time constant on the induced power‐density of the applied field, we show that the model is consistent with published experimental results on power density windowing effects for particular values of model parameters. For these parameter values, the model predicts further power densities where windowing effects may be observed under appropriate conditions. Bioelectromagnetics 21:455–464, 2000. © 2000 Wiley‐Liss, Inc.