... net rate of binding of Ca2+ to the j-th class of Ca2+ buffer (e.g protein); vd, degradation of IP3 (performed mainly by hydrolysis to inositol1,4-bisphosphate or phosphorylation to inositol-1,3,4,5-tetrakisphosphate); ... is the ryanodine receptor (RyR), whose physiological activator appears to be cyclic ADP ribose [44] Opening of the IP3R, in the presence of IP3, and of the RyR is also stimulated by calcium binding ... effect of Ca2+ on IP3 turnover or the sequestration of Ca2+ by mitochondria play a modulatory role and may be cell-type specific Accordingly, if not only the occurrence of spikeshaped oscillations...