Chaos in intracellular Ca2+ oscillations in a new model for non-excitable cells.

A new model for intracellular Ca2+ oscillations is presented. The new model reinterprets two previous models, the ICC and CICR mechanisms, and incorporates the bell-shaped dependence of Ca2+ release on cytosolic [Ca2+]. Complex oscillations and chaos are found with this new model, confirming experimental observations of complex oscillations. A rich bifurcation sequence is found for the model as the stimulation due to agonist (R) is varied, including a period doubling route to chaos and a period-adding sequence of mixed-mode states.