Fig. 7.

Differentiated NHBE monolayers display increased I_sc responses after apical treatment with the selective β₂-adrenergic receptor (AR) agonist salbutamol. A: representative I_sc trace of day 16 monolayers treated apically first with benzamil (5 μM), then with the selective β₂-AR agonist salbutamol (10 μM), and finally with CFTR_inh-172 (20 μM). Apical addition of salbutamol increased I_sc in control HC0 and HC8 monolayers, consistent with stimulated anion secretion. B: summary of benzamil-sensitive, salbutamol-activated, and CFTR-dependent I_sc results in A. *Significant differences between treatment and control conditions (n = 4). C–D: quantitative RT-PCR analysis of β₂-AR (ADRB2) and CFTR mRNAs (n = 6 for each bar). HC0 monolayers showed reduced ADRB2 and CFTR expression at days 8 and 24. E: Western blot analysis of CFTR and ADBR2 in control and HC0 cells (25 ng of total protein). CFTR protein abundance appeared to be reduced in HC0 cells at days 8 and 24. Blue-and-white-striped bars represent undifferentiated control data at day 0 (n = 6 for each bar). *Significant difference between day 0 and each subsequent day of differentiation (by ANOVA followed by Dunnett's test for comparisons with a common control within each treatment condition); °significant difference between HC0 or HC8 and the corresponding day of differentiation in the control group (by ANOVA followed by Tukey-Kramer multiple-comparisons test).