Fig. 2. (  A ) A representative recording of the integrated C4 activity (∫C4) before, during, and after superfusion with 0, 0.23, 0.74, and 1.25 mm (0, 0.77, 2.11, and 3.57 minimum alveolar concentration [MAC], respectively) sevoflurane solution. The  horizontal bars indicate the duration of superfusion with sevoflurane. (  B ) Concentration-dependent effect of sevoflurane on C4 burst rate (  left ) and amplitude (  right ). Higher concentrations of sevoflurane tended to produce a greater decrease in C4 burst rate and amplitude. *  P < 0.05  versus control. **  P < 0.01  versus control.