Fig. 6. Effects of volatile anesthetics on Ca²⁺-activated Cl⁻(Cl^Ca) channel currents (I^Cl(Ca)) recorded in a pipette solution containing 1.8 mm CaCl²and 2.5 mm EGTA. (A ) Effects of 1.5 minimum alveolar concentration (MAC) isoflurane on I^Cl(Ca)evoked by +40-mV depolarizing pulses in a tracheal smooth muscle cell. (B ) Cl^Cacurrent–voltage relation obtained before and after exposure to 1.5 MAC isoflurane and 1.5 MAC sevoflurane in bronchial smooth muscle cells. (C ) Relations between anesthetic potencies (MAC) and I^Cl(Ca)at +40 mV in both tracheal and bronchial smooth muscle cells. Data are expressed as mean ± SD (n = 7 each). *P < 0.05 versus  0 MAC anesthetic.