Electrophysiology
All experiments were performed in the whole‐cell version of the patch‐clamp technique using either an EPC‐9 or EPC‐10 amplifier controlled by Pulse software (HEKA Electronics, Lambrecht, Germany) according to the previously described methodology [18]. HEK293 cells stably expressing human wild-type KCa3.1 channel or THP-1 human monocyte cell line were used. IC50 values for blocking KCa3.1 channels were estimated either from concentration–response curves by fitting to the Hill equation or from a fit to the inhibition kinetics assuming that IC50 = K d as detailed previously [18]. Selectivity experiments using other ion channels were performed as described previously [24].