Figure 3. Effect of volatile anesthetics (here diethylether as an example, cell R4343) on sodium channel steady-state inactivation. (A) Sodium currents were elicited by test pulses to -10 mV after 500 ms-prepulses to potentials varying from -150 to -10 mV. (B) Normalized peak currents are plotted as a function of prepulse potential (circles = control; triangles = -100 mM ether, diamonds = -200 mM ether; squares = washout). Lines are fits to two-level Boltzmann distributions. Currents were normalized to the maximum current before addition of the anesthetic, obtained from the Boltzmann-fits. The midpoint of channel inactivation, obtained from the Boltzmann-fits, shifted from -58.8 mV (control--circles) to -72.0 and -89.1 mV during perfusion with 100 mM (triangles) and 200 mM (diamonds) diethylether, respectively. After washout (squares), it returned to a value of -55.0 mV.