Molecular Mechanisms of Large-Conductance Ca²⁺-Activated Potassium Channel Activation by Ginseng Gintonin

Figure 2

Effects of gintonin on BK_Ca channel activity. (a) Gintonin concentration-response curve (mean ± S.E.M; 𝑛=13–15 oocytes each). Inset, the representative traces of gintonin-mediated BK_Ca channel activation at various concentrations. (b) Effects of gintonin (10 μg/mL) on the current-voltage (𝐼-𝑉) relationship of the wild-type BK_Ca channel (mean ± S.E.M; 𝑛=13–15 oocytes each). (c) Time-current relationship plotted against time before and after repeated applications of gintonin (10 μg/mL) for 30 s in oocytes expressing the BK_Ca channel. Inset, the representative peak outward current amplitude at +40 mV from a holding potential of −80 mV was measured in the absence or presence of gintonin. (d) Summary histograms show that repeated application of gintonin induces the desensitization of gintonin-mediated BK_Ca channel activation (*𝑃<0.001, compared to 1st gintonin treatment). (e) The representative traces on blockage of gintonin-mediated BK_Ca channel activation by the LPA1/3 receptor antagonist, Ki16425. (f) Summary histograms show that gintonin-mediated activation of the BK_Ca channel is blocked by the LPA1/3 receptor antagonist, Ki16425 (mean ± S.E.M; 𝑛=12–14 each) (*𝑃<0.001, compared to gintonin alone).

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