Figure 4.
Inhalation of nicotine aerosols reduced airway CFTR function in ferrets. A: representative electrophysiologic tracings for in vivo nasal potential difference (NPD) measurements in ferrets following 6 wk of nose-only control room air (Air control) or nicotine aerosols (Nicotine). Summary graphs illustrate potential difference (PD) changes in amiloride inhibition of sodium ion transport by ENaC (B) and total CFTR function (C), as estimated by combining voltage changes following perfusion of chloride-free ringers that sets a chloride ion gradient across nasal epithelium and forskolin. CFTR-dependent voltage changes are represented by distinguishing channels in the open conformation (D) at baseline and responded to perfusion of chloride-free ringers and the proportion of channels in the closed conformation (E) at baseline and were activated by forskolin perfusion. F: representative electrophysiological tracings for tracheal explants in Ussing chambers indicating transepithelial ion transport properties. Summary graphs illustrate changes in short-circuit currents (Isc) following amiloride inhibition of ENaC (G) and forskolin-stimulated CFTR-mediated ion transport (H) under an apical chloride ion gradient. I: specific inhibitor GlyH101 distinguished epithelial ion transport that was attributable to CFTR channels. Means ± SD values represent 6–7 ferrets/condition, and statistical significance was interpreted by unpaired, two-tailed, nonparametric Mann–Whitney test; *P < 0.05; **P < 0.005; ***P < 0.0005.