Figure 2. Voltage dependence of hEAG1 channel inhibition by PIP₂.

(A) Representative current traces were recorded at −80 mV following depolarization to different voltages indicated. PIP₂ was applied at 2 μM. (B) Normalized conductance under the conditions shown in (A). The results obtained in the presence of PIP₂ (2 μM) were normalized to the maximal conductance inferred from the tail currents before PIP₂ application in each patch. The normalized conductance values were 0.94 ± 0.02, 0.51 ± 0.04 and 0.81 ± 0.04, respectively (n  =  6). (C) Illustrative current traces elicited by pulses from −80 to 50 mV in 10 mV increments before and after application of 0.1 μM PIP₂. (D) Peak current-voltage curves from the results shown in (C). (E) Normalized conductance-voltage (GV) curves constructed from hEAG1 channel tail currents before and 3–5 min after application of 0.1 μM PIP₂. The curves were fitted with a Boltzmann function from the results obtained using the same protocol as in (C). The fit parameters, half-activation voltage (V_0.5) and slope factor (k), of voltage-dependent activation of hEAG1 channels before and after PIP₂ application (0.1 μM) are shown in (F). **P < 0.01 compared to the control before PIP₂ application and ^††P < 0.01 compared to after PIP₂ application at 40 mV.