Figure 6-4 Relaxation of 5-hydroxytryptamine-preconstricted rat bronchial segments with intact (A) and disrupted (B) epithelium to increasing concentrations of desflurane, sevoflurane, isoflurane, and halothane expressed as minimum alveolar anesthetic concentration (MAC) multiples. Desflurane was a more potent bronchodilator than sevoflurane (A), which was more potent than either halothane or isoflurane. Rubbing epithelium significantly blunted the bronchodilatory effects of all anesthetics (B). There were no differences between the agents. (Adapted from Park KW, Dai HB, Lowenstein E, et al: Epithelial dependence of the bronchodilatory effect of sevoflurane and desflurane in rat distal bronchi. Anesth Analg 86:646, 1998.)