Figure 3.

Whole-cell simulations. (A) Shown here is a simulated AP in a neuronal model (20) with 1:n stoichiometry BK_Ca-CaV complexes with n = 1 (cyan), n = 2 (green), or n = 4 (red). The whole-cell BK_Ca current is described by Eq. 28 (i.e., BK_Ca coupled with noninactivating CaVs), where the BK_Ca activation, $m_{BK}^{\left(n\right)}$, is modeled by Eq. 26 (see Eq. S36 for the details) and g_BK = 1 mS cm⁻². The blue curve shows the case of BK_Ca block (g_BK = 0 mS cm⁻²), and the trace in black displays the result with n = 1, g_BK = 4 mS cm⁻². The inset shows a zoom-in on the fAHP. (B–D) Shown here are simulated APs in a model of human β-cells (22) with BK_Ca channels located in complexes with n T-type (B), L-type (C), or P/Q-type (D) CaVs, with n = 1, 2, or 4. The whole-cell BK_Ca current is described by Eq. 27 (with inactivating T- and L-type CaVs) or Eq. 28 (with noninactivating P/Q-type CaVs), where $m_{BK}^{\left(n\right)}$ is modeled by Eq. 29. Color coding as in (A). (E–G) Shown here is simulated activity in a model of lactotrophs (21) with 1:n BK_Ca-CaV complexes with n = 1 (E), n = 2 (F), or n = 4 (G). The whole-cell BK_Ca current is described by Eq. 28, where $m_{BK}^{\left(n\right)}$ is modeled by the complete BK_Ca model with 2 × (n + 1) states (Fig. 2A) described using Eqs. S19–S25 (upper traces), by Eq. 26 (middle traces), and by Eq. 29 (lower traces). To see this figure in color, go online.