Figure 3.

Effects of DTT and DTDP on the currents carried by cloned K⁺ channels. Effect of DTT (2 mM) or DTDP (100 μM) on K⁺ currents elicited in depolarizing pulses to +40 mV in cells transfected with Shaker + Kvβ1.2 (A), Kv4.2 (B) or Kv4.2 + Kvβ1.2 (C) channels. DTT or DTDP were applied for 3–5 min. When present, the effects did not revert upon washout with control solution. However, the effect of DTT was reverted by the application of DTDP and vice versa. A, inset, shows the average effects of these two drugs on the current amplitude in cells transfected with Shaker + Kvβ1.2 (n = 4). The effects are expressed as (1 − I/I₀) · 100, I₀ being the current amplitude of the current at the end of the 100-ms depolarizing pulse in control conditions so that inhibitions appear as negative values and potentiations as positive values. C, inset, shows the results of a similar analysis in Kv4.2 + Kvβ1.2-transfected cells (n = 6), but in this case peak current amplitudes were taken.