Fig. 9.

Cat-S stimulates ENaC in confluent M-1 mouse collecting duct cells. a Representative equivalent short-circuit current (I _SC) recordings from confluent M-1 cells pretreated with nafamostate mesylate to reduce constitutive ENaC activation by endogenous proteases. Vehicle control (phosphate buffered saline, upper trace) or Cat-S (2 μM, lower trace) was added to the apical bath solution of M-1 cells. At the end of the experiment, amiloride (ami; 10 μM) was added apically to confirm that the stimulated I _SC was mediated by ENaC. b, c Summary of results from similar experiments as shown in a. b Data points represent individual I _SC values obtained from six (control) or seven (Cat-S) individual experiments that are connected by a line. c Columns represent relative stimulatory effect on ΔI _SC calculated as the ratio of ΔI _SC measured after 20 min of incubation (ΔI _SC 20 min) to the initial I _SC (ΔI _SC initial) measured before apical addition. **p < 0.01, unpaired t test