Figure 6. Lack of use-dependent block of calcium current by sevoflurane. (A) Records of calcium currents during 200-ms pulses to 0 mV from a holding potential of -30 mV. Multiple traces (two traces before applying sevoflurane and the first and the second traces just after the stimulation restarted) are shown. There was no stepwise depression after the stimulation was resumed, indicating absence of use-dependent block in the presence of sevoflurane. (B) Calcium currents were recorded just before applying sevoflurane, and smaller calcium currents were recorded during a series of test pulses at 0.2 Hz starting 600 s after beginning sevoflurane exposure. The graph plots the magnitude of peak value of each calcium current.