Fig. 3. Transient inhibition and desensitization of I_Cl,swell in response to isoproterenol (ISOP). (A) Time course of I_Cl,swell of a representative experiment under isotonic (ISO) and hypotonic conditions in the absence and presence of 1 µM ISOP. Each circle represents the current obtained every 10 seconds at -100 mV (lower trace) and +100 mV (upper trace). Numbers 1-3 indicate time points during the ISOP-induced transient reduction phase of I_Cl,swell, 4 after ISOP wash out and 5-6 during the second ISOP application. (a) and (b) are close ups of the I_Cl,swell time course as indicated by the windows in A. Data were fitted by single exponential functions during I_Cl,swell reduction (black line) and recovery (grey line), respectively. (B) Representative current-voltage relationships (V_mem ramps from -100 mV to +100 mV) recorded under isotonic and hypotonic conditions in the absence and presence of ISOP and after washout of ISOP. (C) Average amplitudes of I_Cl,swell under hypotonic conditions in the absence and presence of 1 µM ISOP. Results of 4-6 individual experiments as shown in panel A (n=4-6). The corresponding time points for every condition (1-6) are indicated in panel A. Asterisks indicate significant differences to control (CO). Hashes indicate significant differences as indicated. Means±SEM; ** p<0.01; # p<0.05, ## p<0.01.