Fig. 2. Concentration-dependent effects of anesthetics on 5-hydroxytryptamine (5-HT)–induced currents in the 5-HT3receptor. The study compared the effects on 1 μm 5-HT (EC15)–induced currents of anesthetics at concentrations of 0.5, 1, 2, and 4% halothane, isoflurane, and sevoflurane and at concentrations of 35, 70, and 100% N2O and Xe. Values are expressed as percent of the control response without anesthetics. Halothane and isoflurane potentiated the 5-HT3receptor, but sevoflurane, N2O, and Xe inhibited 5-HT–induced currents in a concentration-dependent manner (P < 0.05 vs. control). Data from more than five oocytes were expressed as mean ± standard error of the mean.