Fig. 3

In vivo ATP release under basal conditions and after isoproterenol treatment. (A) Basal ATP release during continuous saline perfusion (5 ml/min) was measured in vivo. Mean data (± standard error of the mean; SEM) from normal (open squares; n = 5) and cystic fibrosis (CF; solid circles; n = 5) subjects is depicted. After an initial wash-down in ATP concentration, a stable level typically persisted for ⩾15 min. The inserted figure depicts the mean steady-state rate of ATP release from normal and CF nasal mucosae. (B) Comparison of isoproterenol vs. vehicle on ATP release. Using a hand-held nebulizer, isoproterenol (10 µM) was applied to one nostril in normal (n = 5; solid circles) and CF (n = 4; open squares) subjects, and an equal volume of vehicle (.9% NaCl) to the opposite nostril. Nasal lavages were performed 2 min after applying the respective agents, and ATP and urea concentrations were measured. The ATP concentration after isoproterenol vs. vehicle (corrected for dilution) from each patient is plotted with respect to the line of unity (dashed line).