Conditional probability analysis for a domain model of Ca(2+)-inactivation of Ca2+ channels

The domain model of Ca2+ inactivation of Ca2+ channels, which has been used to explain rapid inactivation of whole cell Ca2+ currents in pancreatic beta cells, is applied to single-time and conditional open probability measurements on guinea pig ventricular myocyte Ca2+ channels. These two measurements greatly constrain the choice of kinetic constants in the model. Calculations with the model provide a simple quantitative explanation of recent experimental results, including a slow increase in the inactivation rate.