Fig. 8. Relations between the percent control peak whole-cell inward Ca2+current (ICa) and the anesthetic potencies (minimum alveolar concentrations [MAC]). The inhibition of peak ICathrough T-type voltage-dependent Ca2+channels in bronchial smooth muscle cells were obtained by digital subtraction of the currents obtained at a holding potential (HP) of −40 mV from total currents elicited from an HP of −80 mV in the same cells. Symbols represent mean ± SD; n = 7; * P < 0.05 versus 0 MAC anesthetic; †P < 0.05 versus L-type of either tracheal or bronchial smooth muscle. Each of the two volatile anesthetics significantly inhibited peak ICain a dose-dependent manner. There was no significant differences between tracheal and bronchial smooth muscles in the inhibitory effects on the L-type ICa; however, both anesthetics induced greater inhibitory effects on T-type ICas in bronchial smooth muscles than on the L-type ICas in either tissue.