Fig. 1

Direct inhibition of Kv1.3 channel currents by CPZ. A Superimposed current traces obtained by applying a series of voltage pulses from -50 mV to + 50 mV upon exposure to 100 µM CPZ for 6 and 12 min. B–G Current–voltage relationship of peak (B, D) and steady-state Kv1.3 channel currents (C, E) in the presence of CPZ with indicated concentrations for 6 min (B, C) or 12 min (D, E). Peak currents were recorded at their peaks, whereas steady-state currents were determined at the end of depolarizing pulses. Peak and steady-state currents at + 50 mV in control conditions were normalized to 1. Concentration–response inhibition of peak and steady-state currents after 6-min (F) or 12-min (G) exposure to CPZ, elicited by a single + 50 mV pulse from a holding potential of − 60 mV (n = 4–13 oocytes per concentration). H Current traces elicited by 2-s depolarization from − 20 to + 50 mV from a holding potential of − 60 mV, with and without 100 µM CPZ exposure. I, J CPZ-induced blockade of peak (I) and steady-state (J) Kv1.3 currents at various voltages for 6 min (n = 5–7 oocytes per treatment). At each depolarizing voltage step, the currents under different CPZ concentrations were normalized to the currents recorded without CPZ exposure. K Comparison of 30 µM CPZ-induced inhibition of peak and steady-state Kv1.3 currents at various voltages for 6 min. Current inhibition (%) = 100 × (current with vehicle—current with CPZ)/current with vehicle. Values are shown as mean ± S.E.M