Figure 7.

Effects of K⁺ channel blockers on the outward Na⁺ currents (I_Na). Currents evoked by step depolarization to 68 mV (top panel) were recorded using the Na⁺-rich pipette solution; left-hand panels show continuous recorded of I_m whilst the right-hand panels shows mean currents quantified over the final 300 ms of the voltage pulse. In each experiment data were recorded during exposure to standard bath solution (control) and after 30–60 s exposure to 0.3 mM quinidine (A, n = 5); 3 mM bupivacaine (B, n = 6); 50 µM clofilium (C, n = 5) and 2 mM 4-AP (D, n = 5). All data are mean ± s.e.m.; asterisks denote statistically significant effects of the test substances (**P < 0.02; ***P < 0.001; Students paired t-test.