Fig. 5.

Lubiprostone challenge in ClC-2 knockout mouse. X-axis units in hours:minutes elapsed. After baseline NPD was recorded, amiloride superfusion led to a modest depolarization consistent with the presence of wild-type CFTR. Shortly after switching to solution 3, chloride transport was induced, consistent with the presence of functional CFTR. Addition of 20 μM lubiprostone did not activate further chloride transport, consistent with the absence of ClC-2. Confirmation of CFTR function occurred with the subsequent exposure to 100 μM isoproterenol in solution 7.