Figure 2.

Open-channel block of Kv1.1 channels by HUFAs. (A) Cartoon illustrating the competition of TEA and AA for pore binding. (B) Block of Kv1.1 by AA alone (τ=17 ms, black fit), by TEA (grey) and by AA in the presence of TEA (τ=132 ms, black fit). (C) Normalized Kv1.1 currents recorded in the presence of different TEA concentrations. The IC₅₀ for TEA was 0.67±0.06 mM (n=3, not illustrated). (D) Time constants of Kv1.1 block by AA in the presence of different TEA concentrations. The filled circles represent the measured time constants of block and the continuous blue line the calculated time constants as a function of the TEA concentration. (E) Block of Kv1.1 by AA at +40 mV. The deactivation tails recorded at −40 mV show a clear cross over. (F–M) Data derived from cell-attached recordings in HEK cells transfected with Kv1.1. (F) Single-channel recordings before and (G) after application of AA. (H) Superposition of the ensemble currents in the absence and presence of AA (average of 12 traces). (I) Amplitude histogram before and after application of AA. (J) Closed-time histogram and (K) histogram of open times within a burst before (black) and after (blue) application of AA. (L) Changes in burst duration and (M) in nP_o induced by AA.