Concentration-dependent block of KCNQ1/KCNE1 by Chromanol 293B.
KCNQ1 and KCNE1 are coexpressed in HEK cells. Example of an original current trace obtained by manual patch clamp is shown in A. In this example, cells are depolarized for 4 sec from -80 mV to +60 mV. The inhibitory effect of chromanol 293B on KCNQ1/KCNE1 was evaluated by measuring the amplitude of the tail current elicited upon return to a holding potential of -50 mV, in the presence of escalating concentrations of test compound. B: Concentration-response curve for reduction of KCNQ1/KCNE1 tail current by chromanol 293B. Data are shown as mean ± SEM (n=3) and are in agreement with the literature (IC50=5.3 uM in Guinea pig cardiac myocytes; Ding et al, Brit J Pharmacol (2002) 137, 253-262.)