Figure 5. Effect of propofol on steady-state inactivation curve. (A) Original current tracings of I^Ca(L) in the absence (a) and presence of 56 micro Meter propofol (b). The voltage protocol is shown at the top of A. Currents were evoked during a test pulse to +10 mV immediately after 30-s prepulses ranging from -60 mV to -10 mV. (holding potential was -90 mV and the stimulation frequency was 0.2 Hz). (B) The steady-state inactivation curves are plotted with normalized current against different prepulses potentials. The data points through smooth lines are fitted with the Boltzmann equation. Note that the addition of 56 micro Meter propofol (filled circles) significantly shifted the inactivation curve to a hyperpolarizing direction, compared with the control (open circles).