Figure 6. BPA-MS activates BK channels containing the β1 subunit over a wide range of voltages. (A) Shows families of current traces from a representative I-O patch taken from a cell expressing BK α (symmetrical 140 mM K⁺; pCa 6.3). The voltage template is shown below. (B) Contains the I-V relationship for this single patch. BPA (100 μM), but not BPA-MS (100 μM), appears to affect current. (C) Contains group data (n = 8) showing that BPA-MS does not shift the midpoint (V½) of the activation curve. (D) Shows families of current traces from a representative I-O patch taken from a cell expressing BK α + β1 (symmetrical 140 mM K⁺; pCa 6.3). A slightly different voltage template is shown below. (E) Contains the I-V relationship for this single patch. Both BPA-MS (100 μM) and BPA (100 μM) appear to affect current. (F) Contains group data (n = 12) showing that BPA-MS and BPA both hyperpolarize the V½, with BPA being more effective. See text for statistical analyses of V½ and k for each set of experiments.