Fig. 4.

Voltage dependence of HERG current blocked by the H₂O fraction of L. erythrocarpa. (A) Current traces from a cell depolarized to -40 mV (left panel), 0 mV (middle panel) and +40 mV (right panel), before and after exposure to 30 µg/mL of the H₂O fraction of L. erythrocarpa, showing increased blockade of HERG current at the more negative potential. The protocol consisted of 4-sec depolarizing steps to -40 mV, 0 mV or +40 mV from a holding potential of -70 mV, followed by repolarization to -60 mV. (B) HERG current inhibition at different voltages by the H₂O fraction of L. erythrocarpa. At each depolarizing voltage step (-40, -20, 0, +20 or +40 mV), the tail currents in the presence of 30 µg/mL H₂O fraction of L. erythrocarpa were normalized to the tail current obtained in the absence of L. erythrocarpa. Bars with error bars represent means±SEM (n=6). (C) Concentration-dependent block of HERG current by the H₂O fraction at different membrane potentials. At each depolarizing voltage step (-30 mV, 0 mV or +30 mV), the tail currents in the presence of various concentrations of the H₂O fraction were normalized to the tail current obtained in the absence of L. erythrocarpa, and plotted against H₂O fraction concentrations. Symbols with error bars represent means±SEM (n=6). The line represents the data fits to the Hill equation.