Fig. 6.

hERG1 concatemers containing one or four G628C/S631C subunits have equal sensitivity to cisapride. (A) Representative current traces recorded at 0 mV for WT₄, GCSC₁/ WT₃ and GCSC₄ hERG1 channels in the absence and presence of 0.3 µM cisapride. (B) [Cisapride]-effect relationship for inhibition of I_test measured at the end of the 4-second pulse to 0 mV for the indicated concatenated hERG1 channels. Data were fitted with a logistic equation (smooth curves) to determine IC₅₀ for WT₄ channels (188 ± 20 nM; data from Fig. 1A), GCSC₁/WT₃ channels (511 ± 48 nM, n = 3), and GCSC₄ channels (487 ± 55 nM, n = 3).