On the role of stochastic channel behavior in intracellular Ca2+ dynamics.
I present a stochastic model for intracellular Ca(2+) oscillations. The model starts from stochastic binding and dissociation of Ca(2+) to binding sites on a single subunit of the IP(3)-receptor channel but is capable of simulating large numbers of clusters for many oscillation periods too. I find oscillations with variable periods ranging from 17 s to 120 s and a standard deviation well in the experimentally observed range. Long period oscillations can be perceived as nucleation phenomenon and can be observed for a large variety of single channel dynamics. Their period depends on the geometric characteristics of the cluster array. Short periods are in the range of the time scale of channel dynamics. Both long and short period oscillations occur for parameters with a nonoscillatory deterministic regime.
Falcke
Martin
M
Hahn Meitner Institute, Glienicker Str. 100, 14109 Berlin, Germany. falcke@hmi.de
D002021:Buffers; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000502:physiology; D020013:Calcium Signaling / Q000502:physiology*; D002462:Cell Membrane / Q000502:physiology; D003198:Computer Simulation; D004058:Diffusion; D004721:Endoplasmic Reticulum / Q000502:physiology*; D053496:Inositol 1,4,5-Trisphosphate Receptors; D015640:Ion Channel Gating / Q000502:physiology; D017136:Ion Transport / Q000502:physiology; D008954:Models, Biological; D008956:Models, Chemical; D015233:Models, Statistical; D018160:Receptors, Cytoplasmic and Nuclear / Q000502:physiology; D012680:Sensitivity and Specificity; D013269:Stochastic Processes
D002021:Buffers; D015220:Calcium Channels; D053496:Inositol 1,4,5-Trisphosphate Receptors; D018160:Receptors, Cytoplasmic and Nuclear; D002118:Calcium