Fig. 5. Effects of sevoflurane on L-type Ca2+channel currents and cloned human cardiac Na+channel currents. ( A ) L-type Ca2+channel currents were recorded from guinea pig myocytes. Currents were generated by 300-ms depolarizing pulses to 0 mV from a holding potential of −40 mV every 5 s. The effects of 0.3 and 3 mm sevoflurane are shown. ( B ) Dose–response relation for sevoflurane block of Ca2+channel current. The IC50approximates 3 mm, the solubility limit for sevoflurane under these conditions. Error bars indicate SEM (n = 6). ( C ) Human cardiac Na+channel (Nav1.5) currents were elicited by 50-ms step depolarizations to −20 mV from a holding potential of −90 mV every 5 s. The effects of 0.3 and 3 mm sevoflurane are shown. ( D ) Dose–response relation for sevoflurane inhibition of peak Na+channel currents. Data were obtained from a holding potential of −90 mV ( open squares ) or −70 mV ( open circles ). Error bars denote SEM (n = 6).