A quantitative kinetic model for ATP-induced intracellular Ca2+ oscillations.

A quantitative kinetic model is proposed to simulate the ATP-induced intracellular Ca(2+) oscillations. The quantitative effect of ATP concentration upon the oscillations was successfully simulated. Our simulation results support previous experimental explanations that the Ca(2+) oscillations are mainly due to interaction of Ca(2+) release from the endoplasmic reticulum (ER) and the ATP-dependent Ca(2+) pump back into the ER, and the oscillations are prolonged by extracellular Ca(2+) entry that maintains the constant Ca(2+) supplies to its intracellular stores. The model is also able to simulate the sudden disappearance phenomenon of the Ca(2+) oscillations observed in some cell types by taking into account of the biphasic characteristic of the Ca(2+) release from the endoplasmic reticulum (ER). Moreover, the model simulation results for the Ca(2+) oscillations characteristics such as duration, peak [Ca(2+)](cyt), and average interval, etc., lead to prediction of some possible factors responsible for the variations of Ca(2+) oscillations in different types of cells.