Figure 1. Representative tracings of transrectal potential difference (PD) measurements in baseline conditions in a wild-type mouse and a F508del homozygous mouse.

Tracings show sequential response of the rectal mucosa to perfusion successively with Ringer solution, Ringer solution containing barium and amiloride (Amil), chloride-free solution containing barium and amiloride (0 Cl⁻), and chloride-free solution with barium, amiloride and forskolin. Arrows indicate time of solution changes.