Figure 8. Effects of isoflurane, enflurane, and sevoflurane on the relaxation elicited by low concentrations of acetylcholine (ACh) in the endothelium-intact strips precontracted with norepinephrine (NE, 10 micro Meter). (A-C) Examples of the inhibitory effects of isoflurane, enflurane, and sevoflurane on the ACh (0.03–0.3 micro Meter)-induced relaxation. The left, middle, and right panels of each figure show the ACh relaxation before exposure to the anesthetics (precontrol), in the presence of the anesthetics, and after washout of the anesthetics from the bath (postcontrol), respectively. W = washout of ACh and NE. (D) Inhibitory effects of isoflurane, enflurane, and sevoflurane on the NE (10 micro Meter)-induced contractions. NS = no significant differences between the groups. (E) The open circles, closed circles, and open triangles show the precontrol ACh relaxation, the ACh relaxation in the presence of the anesthetics, and the postcontrol ACh relaxation, respectively. No significant difference were observed in the ACh relaxation between the precontrol and postcontrol groups in all experiments. Values are mean plus/minus SD (n = 6–9). *P < 0.05 versus pre- and postcontrol at each concentration.