Figure 9. Analysis of the voltage sensitivity of correolide (COR)-sensitive K_V1 current.

A, pulse protocol used to assess the effect of 1 μM correolide (COR) on K⁺ channel activation in symmetrical K⁺ solutions. The two superimposed tail currents evoked by a voltage step from −70 to +58 mV demonstrate COR-sensitive tail currents. B, the effect of 1 μM COR on steady-state activation (n = 6). Values were provided by tail current analysis. C, pulse protocol used to assess the effect of 1 μM COR on inactivation in physiological K⁺ gradients. Superimposed traces were evoked by inactivating pre-pulses of −86, −14 and +18 mV, followed by a depolarizing step to +58 mV after a 5 ms delay at −70 mV to evaluate available current. D, the effect of 1 μM COR on steady-state inactivation (n = 7). Values were provided by experiments detailed in C. E, activation and inactivation relationships for COR-sensitive current. Values were obtained by subtracting COR-insensitive current from total K⁺ current, and were fitted with a Boltzmann function. The V_0.5 value for activation was −1 mV and k was 14, whereas the V_0.5 value for inactivation was −37 mV and k was 12. Data are expressed as means ±s.e.m. (n = 6–7). * Significant difference (P < 0.05) between control and experimental values at the same voltage.