Figure 3.
Representative tracings of nasal potential difference (PD) measurements in wild-type (WT) and F508del-CF (CF) mice 24 h after placebo (saline) or vardenafil (single i.p. dose of 0.14 mg/kg body weight). Tracings show sequential response of the nasal surface to perfusion successively with basal solution, basal solution with 10−4 M amiloride (amil), chloride-free solution plus amiloride (0 Cl), and chloride-free solution with amiloride plus 10–5 M forskolin (forskolin). Arrows indicate change of solutions. As illustrated, basal values and amiloride response are not influenced by vardenafil treatment. However, chloride secretion (difference between values obtained at the end of the test and the end of the amiloride phase) is restored in CF animals and the effect lasts at least 24 h after vardenafil treatment (Lubamba et al., 2008).