Dynamic control of inositol 1,4,5-trisphosphate-induced Ca2+ release: a theoretical explanation for the quantal release of Ca2+.

A theoretical model has been elaborated in order to describe the kinetics of Ca2+ release induced by inositol 1,4,5-trisphosphate (IP3). The model is based on the existence of a key molecule that controls the interconversion of open and closed forms of the Ca2+ channel. The model can quantitatively explain the previously obtained experimental observations that showed that a continuous IP3 stimulus leads to a biphasic Ca2+ release and that successive IP3 additions provoke repetitive bursts of Ca2+ release. Other published interpretations of these observations are discussed.