Figure 2.

The inhibition of peak μ1-wild-type (A) and μ1-N434K (B) Na⁺ currents by external 200 μM veratridine was measured by a test pulse (+50 mV for 6 ms) under equal internal/external Na⁺ ion concentrations. Trace 1 represents the current recorded 3 min after drug application; control traces before drug are not labeled. Repetitive pulses (shown below) elicited only a small use-dependent inhibition of peak μ1-wild-type (C) and μ1-N434K (D) Na⁺ currents. With superfusion of 200 μM veratridine for 5 min, repetitive pulses elicited significant use-dependent inhibition of peak μ1-wild-type (E) and μ1-N434K (F) Na⁺ currents. Current traces corresponding to 1, 3, 5, 10, 20, 30, 40, 50, and 60 pulses are superimposed.