FIGURE 9.

Computer modeling of Ca²⁺ current deactivation and inactivation in the presence of Ca²⁺ agonist. The kinetic scheme is shown in A. This scheme is an analog to that used in the absence of Ca²⁺ agonists. The asterisks indicate channel states with Ca²⁺ agonist bound. The transition rate constants are listed in Table 3. In B, computer simulations of tail current decay time courses with (b) or without (a) preconditioning depolarization, which induces conversion of Ca²⁺ channel conformation from O₁^* to O₂^*. The voltage dependence of inactivation (C) and Ca²⁺ channel current evoked by depolarization to 0 mV was obtained by the same procedures used in Fig. 8, C and D.