Fig. 4

Electrophysiological characterization of soluble venom. The effect of soluble Centruroides hirsutipalpus venom on sodium and potassium ion channels. From panels A to G: sodium currents of hNav 1.1 to 1.7 channels, respectively. On the right side of each panel are represented the current traces elicited with stimulus at − 10 mv (maximal current) and at − 50 mv (sub-threshold stimulus). Black lines are for control and grey lines are for venom application. In (a) hNav 1.1, (b) hNav 1.2 and (f) hNav 1.6, venom produced current at − 50 mV (arrow) and reduction of the maximal current. The (c) hNav 1.3, (d) hNav 1.4, (e) hNav 1.5 and (g) hNav 1.7 were insensitive to the venom. In each panel, on the left, are represented the activation (circlet) and the inactivation (squares) curves. Full symbols are for the control and empty symbols are for the venom. Grey line are the best fit from a Boltzmann equation or the sum of two Boltzmann equations. In (a), (b) and (f) venom moves activation curve to more negative potentials. (h) Venom produced current reduction on hKv 1.1 channels. The left side shows current in control (black line) and after venom application (grey line). On the right, current values were plotted against time and data were fitted with a first-order exponential equation. Grey line is the best fit of the on-kinetic data and light gray line is the best fit of the off-kinetic data. (i) Venom produced current reduction on hERG1 channels. The left side shows current in control (black line) and after venom application (grey line). On the right, current values were plotted against time and data were fitted with a first-order exponential equation. Grey line is the best fit of the on-kinetic data and light gray line is the best fit of the off-kinetic data. Scaler is 1 ms and 1 nA in panels (a), (b), (c), (e), (g); 1 ms and 0.5 nA in panels (d), (f); 50 ms and 1 nA in panels (h) and (i)