Figure 3. The inhibitory effect of cholesterol on HERG K+ currents is blocked by intracellular PtdIns(4,5)P2 or edelfosine. Cells were incubated with 25 μM or 100 μM MβCD-cholesterol for 1–2 h at 37 °C before recordings. In some recordings cells were treated with MβCD-cholesterol along with PLC inhibitor, 5 μM edelfosine (Chol+Edel) or 25 μM PtdIns(4,5)P2 was included in the pipette solution (Chol+PtdIns(4,5)P2). (A and C) Averaged current-voltage relations obtained for HERG K+ currents (n = 7), measured at the end of the depolarizing step following the step to −40 mV as described in Figure 1 (Istep). (B and D) The peak tail HERG K+ currents amplitude were measured (n = 7) following the step to −40 mV (I peak).