Pharmacological activation of CFTR chloride channels activity in rat airway smooth muscle cells. A Iodide efflux responses as a function of time evoked by 250 μM MPB-07, MPB-91 and MPB-80. All experimental conditions have been repeated: n = 4. Basal was vehicle alone. B Summary of the data for each experimental condition after stimulation by MPB-07, MPB-80, MPB-91. C Iodide efflux response as a function of time evoked by MPB-91 (250 μM) and 10 μM CFTRinh-172. D Effect of 100 μM glibenclamide, 500 μM DPC, 500 μM DIDS, 100 nM calixarene and 10 μM CFTRinh-172 on the efflux stimulated by MPB-91 (250 μM) in rat tracheal smooth muscle cells as indicated. Basal was vehicle alone. Data are presented as mean ± S.E.M. All experimental conditions have been repeated: n = 4. *** P < 0.001, * P < 0.05. ns: non-significant difference.