Bifurcation Scenarios of a Modified Mathematical Model for Intracellular Ca²+ Oscillations

The contribution of this work is the modification of a mathematical model for bursting Ca²⁺ oscillations by introducing the proportion of receptors not inactivated by Ca²⁺ as a new variable. Generation mechanisms of different oscillatory patterns in this modified model are investigated and classified, based on fast/slow dynamical analysis. It is shown that periodic oscillations appear around the original chaotic regions. Moreover, two new types of oscillatory phenomena are observed at the sustaining region. The results may be instructive for understanding the difference between direct observation of dynamical behavior in real cells and theoretical explanations under a variety of stimulus conditions. (paper)