Figure 5
Inhibition of transapical and transbasolateral Isc levels by verapamil in permeabilized H441 monolayers. (A) Representative Isc traces obtained in basolateral permeabilized H441 monolayers with amphotericin B (am B). 1 mM ouabain was added to the basolateral side to exclude any potential residual Isc across basolateral membrane. Amiloride (100 μM) was applied at the end of recording to calculate basal amiloride-sensitive (AS) Isc level as indicated between dashed lines. (B) AS Isc levels before (Basal) and after water (H2O) and verapamil (Verapamil). Paired t-test. ***P < 0.001. n = 4-8. (C) Representative Isc trace recorded in apically permeabilized H441 monolayers with amphotericin B. 100 μM amiloride was added to the apical compartment to inhibit possible residual Isc level carried by ENaC. Ouabain (1 mM) was added at the end of the recording to calculate total ouabain-sensitive (OS) Isc level. (D) Mean OS Isc levels in the absence (Basal) and presence of water (H2O) and verapamil (Verapamil). Paired t-test. *P < 0.05. n = 4.