A model of calcium regulation in smooth muscle cell.
A model of smooth muscle cell is proposed to describe the mechanisms by which intracellular calcium (Cai) is regulated when the cell is stimulated by noradrenaline (NA)/agonist (Ag) or depolarized. The intracellular Ca2+ store is comprised of two calcium pools: A-store which is sensitive to inositol 1,4,5 trisphosphate (IP3) and C-store, insensitive to IP3 but sensitive to Cai. The A-store is refilled by Ca2+ from C-store and reuptake of Cai. The uptake rate is dependent on the degree of filling in the A-store. The C-store, activated by Cai, is replenished by extracellular Ca2+ (Cao). IP3 generated by NA or Ag changes the A-store permeability, discharging its Ca2+ into the cytosol. Depolarization activates Ca2+ current through the L-type channels. The following events are simulated and compared with experimental observations: (a) Cai transient stimulated by high K+; (b) Cai transient and Ca2+ efflux induced by shortlasting and longlasting NA in the absence of Cao; (c) effect of lanthanum on NA-induced Cai and Ca2+ efflux; and (d) effects of nifedipine, ryanodine, BAY K 8644 and cyclopiazonic acid on Cai.
Department of Physiology and Biophysics, Dalhousie University, Halifax, Canada.
A Y
AY
Wong
G A
GA
Klassen
D000818:Animals; D002118:Calcium / Q000378:metabolism* / Q000494:pharmacology; D015220:Calcium Channels / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D015544:Inositol 1,4,5-Trisphosphate / Q000494:pharmacology; D007700:Kinetics; D007811:Lanthanum / Q000494:pharmacology; D008962:Models, Theoretical; D009119:Muscle Contraction; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism*; D009638:Norepinephrine / Q000031:analogs & derivatives / Q000494:pharmacology*; D012433:Ryanodine / Q000494:pharmacology
D015220:Calcium Channels; D012433:Ryanodine; D007811:Lanthanum; D015544:Inositol 1,4,5-Trisphosphate; D002118:Calcium; D009638:Norepinephrine