CHANNELS, RECEPTORS, AND ELECTRICAL SIGNALING |
DYNAMICS OF A 3-VARIABLE NONLINEAR MODEL OF VASOMOTION:
COMPARISON OF THEORY AND EXPERIMENT
Dimitris Parthimos 1, Rebecca Haddock 2, Caryl E Hill 3 and Tudor Griffith 1*
1 Cardiff University
2 UNSW
3 Division of Neuroscience, John Curtin School of Medical Research
* To whom correspondence should be addressed. E-mail: griffith{at}cardiff.ac.uk.
Submitted on February 9, 2007
Revised on March 21, 2007
Accepted on 20 April 2007
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Abstract |
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The effects of pharmacological interventions that modulate Ca2+ homeodynamics and membrane potential in rat isolated cerebral vessels during vasomotion (i.e. rhythmic fluctuations in arterial diameter) were simulated by a 3rd order system of nonlinear differential equations. Independent control variables employed in the model were [Ca2+] in the cytosol, [Ca2+] in intracellular stores and smooth muscle membrane potential. Interactions between ryanodine- and InsP3-sensitive intracellular Ca2+ stores and transmembrane ion fluxes via K+ channels, Cl- channels and voltage-operated Ca2+ channels were studied by comparing simulations of oscillatory behaviour with experimental measurements of membrane potential, intracellular free [Ca2+] and vessel diameter during a range of pharmacological interventions. The main conclusion of the study is that a general model of vasomotion that predicts experimental data can be constructed by a low order system that incorporates nonlinear interactions between dynamical control variables.
Key Words:
InsP3, artery, calcium, ryanodine, smooth muscle
