The K<sub>Ca</sub>3.1 channel does not regulate epithelial mucus production or secretion.

<p>(<b>A</b>) Recombinant human amphiregulin (rh-AR) upregulated MUC5AC mRNA expression in H292 cells cultured in 6 well plates in a concentration-dependent manner after 24 h (*P = 0.010; **P = 0.028; n = 3 individual experiments). (<b>B</b>) Pre-treatment of H292 cells with the K<sub>Ca</sub>3.1 blocker TRAM-34 (200 nM) for 30 min prior to stimulation with 10 ng/ml rh-AR for 24 h did not prevent rh-AR-induced MUC5AC mRNA expression (*P = 0.008, **P = 0.042; n = 6 individual experiments). rh-AR dose-dependently increased the mucin content of (<b>C</b>) H292 ALI culture lysates (*P = 0.029; n = 3 individual experiments) and (<b>D</b>) H292 ALI culture apical washes (*P = 0.009; n = 4 individual experiments) after 24 h, analysed by ELLA. Pre-treatment of H292 ALI cultures with 200 nM TRAM-34 did not prevent rh-AR-induced upregulation of mucin content within (<b>E</b>) H292 lysates (*P = 0.019; n = 6 individual experiments) or (<b>F</b>) apical washes (*P = 0.027; n = 3 individual experiments). Data are expressed as mean ± SEM.</p>