Figure 4.

Alkylamides block TRESK channel currents. A. Representative recording of IBA (500 μM) or Lamotrigine (Lam; 100 μM) -evoked inhibition of TRESK in HEK293 transfected cells. Total background currents (Bkg) were recorded in the whole cell configuration of the patch clamp technique (Holding potential = -60 mV). Vehicle (Veh) did not produce significant effects on recorded currents. B. Quantification of IBA and Lam effects on TRESK and other K_2P channels. n = 5-7 cells per condition. *p < 0.05; **p < 0.01; ***p < 0.001. t-test vs. resting background currents. C. Quantification of IBA and Lam effects on resting membrane voltage in HEK293 cells transfected with TRESK (n = 4 cells per condition). Membrane voltage was normalized with resting membrane. After achieving the whole cell configuration, the patch amplifier was switched to the current-clamp mode and resting membrane voltage was recorded. *p < 0.05 t-test vs. vehicle application D. Representative membrane voltage recordings of TRESK-transfected cells stimulated with IBA (500 μM) or Lamotrigine (100 μM). E. Effect of IBA (400 μM) on total current from DRG neurons. A voltage ramp protocol from -110 to +50 mV was used. A significant decrease (p < 0.01; n = 6) in total current is seen after IBA application compared to Basal current (before IBA application). F. Effect of IBA (400 μM) on currents from DRG neurons using a protocol composed by a depolarizing pulse to -25 mV (holding voltage -60 mV) followed by a hyperpolarizing ramp to -135 mV (as in Fig 2). Quantification of currents is shown at -25 mV (measured at the end of the pulse) and -135 mV. *p < 0.05 vs. basal current. A representative recording is shown. Some TTX-resistant sodium currents can still be observed.