Fig 2. In ferret trachea, PGE₂ stimulated I_sc is mediated by CFTR and Ca²⁺-activated Cl^- channels.

A. Representative I_sc trace with vertical deflections indicating the change in I_sc after a 1 mV pulse was applied (every 1 minute). Ferret trachea was exposed to serosal to mucosal Cl^- gradient with equivalent bilateral HCO₃^-. PGE₂ (1 μM, serosal) was added to ferret trachea after a baseline period of ≥ 10 minutes, with CFTR_inh-172 (20 μM, mucosal) added after 30 minutes. B. Representative I_sc trace of ferret trachea incubated in CFTR_inh-172 (20 μM, mucosal) for at least 30 minutes prior to PGE₂ (1 μM, serosal) stimulation. After 30 minutes, niflumic acid (100 μM, mucosal) was added. C. Change in PGE₂-stimulated I_sc (mean ± SEM, n ≥ 5) in ferret trachea, with comparisons between no inhibition, CFTR inhibition, or CFTR and Ca²⁺-activated Cl^- inhibition. Asterisks denote significance by Student’s t-test (*, P < 0.05, **, P < 0.01). Mean percent inhibition compared to PGE₂ stimulation alone noted.