Lopinavir (LPV) activated ICl,swell via mitochondrial ROS production but not NADPH oxidase. (A, B) LPV (15 μM, 25 min) elicited outwardly rectifying Cl− current that was completely blocked by DCPIB. (C) Current densities at +60 mV showing block of LPV-induced current by DCPIB (n = 5, Ctrl vs. LPV, P <0.001; LPV vs. +DCPIB, P <0.001; Ctrl vs. +DCPIB, P = 0.55), ebselen (n = 5, Ctrl vs. LPV, P <0.001; LPV vs. +Ebselen, P <0.001; Ctrl vs. +Ebselen, P = 0.72), and rotenone (n = 4, Ctrl vs. LPV, P <0.003; LPV vs. +Rot, P <0.006; Ctrl vs. +Rot, P = 0.45). In contrast, LPV-induced current was unaffected by apocynin (n = 4, Ctrl vs. LPV, P <0.001; LPV vs. +Apo, P = 0.79; Ctrl vs. +Apo, P <0.001).