Extending the IP3 receptor model to include competition with partial agonists

► Extend De Young-Keizer IP3 receptor model to include data on partial agonists (PA). ► Li-Rinzel like reduction applied to 12-state model. ► Good qualitative agreement for increasing PA and increasing IP3 with PA present. ► PA non-invariantly shifts calcium-IP3 bifurcation diagram toward higher IP3 levels. ► 2-D simulation shows amplitude decay and slowdown of calcium wave in presence of PA.