Effects of HCP on the outward current of different KCNQ channels.

I/I0 indicates the compounds’ effects on amplitude of outward current of KCNQ channels. I0: the amplitude of outward current in the absence of the compound. I: the amplitude of outward current in the presence of the compound. To calculate I/I0, the depolarization is +50 mV for KCNQ1/KCNE1 and is −10 mV for all other subtypes. ΔV1/2 indicates the shifting of G-V curve. To calculate V1/2, the tail current elicited by followed −120 mV was measured. The concentration of HCP was 10 μM. For KCNQ3, the ΔV1/2 was not available (NA) because the KCNQ3 currents at low voltage potentials were too small to be measured accurately. * p