Fig. 5. Reversible persistent inhibition and desensitization of I_Cl,swell in response to the PKA inhibitor H89. (A) Time course of I_Cl,swell of a single experiment under isotonic (ISO), hypotonic and hypotonic conditions in the absence and presence of H89. Each circle represents the current obtained every 10 seconds at -100 mV (lower trace) and +100 mV (upper trace). 1, I_Cl,swell during hypotonicity; 2, during the application of H89; 3, after H89-washout; 4-5, during second application of H89. (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 H89. (C) Mean amplitudes of I_Cl,swell under hypotonic conditions in the absence and presence of 1 µM H89 as shown in panel A (n=3-8 for conditions 1-3; conditions 4-5 are the means of two single observations (n=2). The corresponding time points for every condition 1-5 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.