Buffers and oscillations in intracellular Ca2+ dynamics.
I model the behavior of intracellular Ca(2+) release with high buffer concentrations. The model uses a spatially discrete array of channel clusters. The channel subunit dynamics is a stochastic representation of the DeYoung-Keizer model. The calculations show that the concentration profile of fast buffer around an open channel is more localized than that of slow buffers. Slow buffers allow for release of larger amounts of Ca(2+) from the endoplasmic reticulum and hence bind more Ca(2+) than fast buffers with the same dissociation constant and concentration. I find oscillation-like behavior for high slow buffer concentration and low Ca(2+) content of the endoplasmic reticulum. High concentration of slow buffer leads to oscillation-like behavior by repetitive wave nucleation for high Ca(2+) content of the endoplasmic reticulum. Localization of Ca(2+) release by slow buffer, as used in experiments, can be reproduced by the modeling approach.
Falcke
Martin
M
Hahn Meitner Institute, Glienicker Str. 100, 14109 Berlin, Germany. falcke@hmi.de
D002021:Buffers; D002118:Calcium / Q000378:metabolism*; D020013:Calcium Signaling / Q000187:drug effects / Q000502:physiology*; D002462:Cell Membrane / Q000502:physiology; D003198:Computer Simulation; D004721:Endoplasmic Reticulum / Q000502:physiology*; D015640:Ion Channel Gating / Q000187:drug effects / Q000502:physiology*; D017136:Ion Transport / Q000502:physiology; D008954:Models, Biological; D008956:Models, Chemical; D012680:Sensitivity and Specificity; D013269:Stochastic Processes
D002021:Buffers; D002118:Calcium