Figure 4.

Ca²⁺ dependence of IP₃R channel modal behavior. (A) Channel open probability $P_{\text{o}}^{\text{M}}$ in various gating modes, (B) relative prevalence π^M, and (C) mean lifetimes τ^M of the various modes (M can be L, I, or H). Symbols and curves represent the mean modal gating characteristics and theoretical fits, respectively. Symbols and curves for different modes are: triangles and solid lines, H; bullets and dashed lines, I; squares and dotted lines, L. Error bars in A–C are smaller than the symbols. The experimental data are taken from Ionescu et al. (2007) (supplemental text, section 1.10.2).