Sneyd, Dufour, 2002
This CellML model runs in OpenCell and COR and the units are consistent throughout. The model runs to recreate published results and is currently configured to recreate Figure 4 (Lower Plot, Trace 4), but variation of the IP3 and Calcium concentrations will allow the model to recreate different figures.
ABSTRACT: The dynamic properties of the inositol (1,4,5)-trisphosphate (IP(3)) receptor are crucial for the control of intracellular Ca(2+), including the generation of Ca(2+) oscillations and waves. However, many models of this receptor do not agree with recent experimental data on the dynamic responses of the receptor. We construct a model of the IP(3) receptor and fit the model to dynamic and steady-state experimental data from type-2 IP(3) receptors. Our results indicate that, (i) Ca(2+) binds to the receptor using saturating, not mass-action, kinetics; (ii) Ca(2+) decreases the rate of IP(3) binding while simultaneously increasing the steady-state sensitivity of the receptor to IP(3); (iii) the rate of Ca(2+)-induced receptor activation increases with Ca(2+) and is faster than Ca(2+)-induced receptor inactivation; and (iv) IP(3) receptors are sequentially activated and inactivated by Ca(2+) even when IP(3) is bound. Our results emphasize that measurement of steady-state properties alone is insufficient to characterize the functional properties of the receptor.
The original paper reference is cited below:
A dynamic model of the type-2 inositol triphosphate receptor, James Sneyd and Jean-Francois Dufour, 2002, Proceedings of the National Academy of Sciences , 99, 2398-2403. PubMed ID: 11842185
|A simplified diagram of the IPR model, where R represents the free receptor, O is the open state of the channel, A is the activated state of the channel and I1, I2, and S are three inactive states.|