Fig. 6. Time courses of the transepithelial voltage normalized to the percentage of the control value (–29 mV and –58 mV, respectively), showing the effects of DPC (0.5 mmol l^-1) during time period 1 and of DIDS (0.1 mmol l^-1) during time period 2. During the time periods denoted w, perfusion of the preparation was changed to withdrawal mode, establishing the bathing solution also on the luminal side of the epithelium. Infusion mode was used during the rest of the time.