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].