Figure 6. Relaxation of the 5-hydroxytryptamine-preconstricted bronchial segments to increasing concentrations of isoflurane or halothane expressed as minimum alveolar concentration multiples (MAC). The two anesthetics appear to be equipotent bronchodilators at equivalent MAC multiples. (One MAC in rats was considered 1.20% isoflurane or 0.88% halothane. [17])