Dynamics of a three-variable nonlinear model of vasomotion: comparison of theory and experiment.
The effects of pharmacological interventions that modulate Ca(2+) homeodynamics and membrane potential in rat isolated cerebral vessels during vasomotion (i.e., rhythmic fluctuations in arterial diameter) were simulated by a third-order system of nonlinear differential equations. Independent control variables employed in the model were [Ca(2+)] in the cytosol, [Ca(2+)] in intracellular stores, and smooth muscle membrane potential. Interactions between ryanodine- and inositol 1,4,5-trisphosphate-sensitive intracellular Ca(2+) stores and transmembrane ion fluxes via K(+) channels, Cl(-) channels, and voltage-operated Ca(2+) channels were studied by comparing simulations of oscillatory behavior with experimental measurements of membrane potential, intracellular free [Ca(2+)] 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.
Parthimos
D
D
Wales Heart Research Institute, Department of Diagnostic Radiology, Cardiff University, Cardiff, UK.
Haddock
R E
RE
Hill
C E
CE
Griffith
T M
TM
D000465:Algorithms; D000818:Animals; D001703:Biophysics / Q000379:methods*; D002118:Calcium / Q000378:metabolism*; D018118:Chloride Channels / Q000737:chemistry; D053496:Inositol 1,4,5-Trisphosphate Receptors / Q000378:metabolism; D008297:Male; D008564:Membrane Potentials; D018715:Microscopy, Video; D008962:Models, Theoretical; D009068:Movement; D015221:Potassium Channels / Q000737:chemistry; D051381:Rats; D017208:Rats, Wistar; D012433:Ryanodine / Q000737:chemistry
D018118:Chloride Channels; D053496:Inositol 1,4,5-Trisphosphate Receptors; D015221:Potassium Channels; D012433:Ryanodine; D002118:Calcium