Figure 4.
Effects on the opening and closing kinetics of the WT Shaker KV channel. (A) Effect of 100 µM Cmpd 5 on the opening at +60 mV. Holding voltage, −80 mV; extracellular solution, 100K; black curve, control solution; red curve, compound solution. Single exponential curves (dashed lines) were fitted from 1.5 to 30 ms. τ(control) = 1.01 ms, τ(Cmpd 5) = 0.88 ms. (B) Effect of 100 µM Cmpd 5 on the closing at −60 mV. Prepulse voltage = +60 mV for 100 ms. Extracellular solution, 100K; black curve,control solution; red curve, compound solution. Tail currents were normalized to the current at the end of the activation pulse. Single exponential curves (dashed lines) were fitted to the tail currents after removal of capacitive spikes. τ(control) = 1.88 ms, τ(Cmpd 5) = 10.8 ms. (C) Effect of 100 µM Cmpd 5 on time constants at different voltages. Time constants for channel opening (as in A but 1K solution, open symbols). Time constants for channel closing (as in B, closed symbols). Black symbols, control solution; red symbols, compound solution. (D) Same as in A but Cmpd 6. τ(control) = 0.89 ms, τ(Cmpd 6) = 1.20 ms. (E) Same as in B but Cmpd 6. τ(control) = 1.22 ms, τ(Cmpd 6) = 10.6 ms. (F) Same as in C but Cmpd 6.