Benzbromarone (Benzb) hyperpolarizes, whereas Eact depolarizes human airway smooth muscle cells. (A) Representative tracings of continuous fluorescence recordings of membrane potential using fluorescent imaging plate reader potentiometric indicator. Eact and potassium gluconate (K-gluc) depolarize, whereas NS1619 (K⁺-channel opener) and Benzb hyperpolarize human airway smooth muscle cells. K-gluc and NS1619 were used as controls because they are known to depolarize and hyperpolarize, respectively. (B) Quantitative change in relative fluorescent units (RFU) showing a decrease in RFU with NS1619 (n = 12) and Benzb (n = 9) and an increase with K-gluc (n = 10) and Eact (n = 9; ***P < 0.001). dmso = dimethyl sulfoxide.