Example of short circuit current data from a MUAS-chamber. A: Typical responses from compounds applied apically and/or basolaterally. a: amiloride, b: theophylline, c: indomethacin, e: cAMP (basolateral), g: db-cAMP (basolateral), h: bumetanide, and i: acetazolamide. d: and f: apically applied cAMP and db-cAMP, respectively. B-E: Typical examples of induced SCC by the four model compounds.