Effect of theophylline on ion transport in the lizard colon.
1. The effect of theophylline on ion transport was examined using an in vitro short-circuited preparation of lizard colon. 2. Theophylline increased short circuit current (Isc) and transmural potential difference (PD). This increase caused by theophylline was accompanied by a small increase in transmural conductance (Gt). 3. Theophylline did not inhibit the absorption of Na+ but reversed Cl- absorption to secretion. This latter effect was due to an increase of the serosal-to-mucosal flux of Cl-. 4. Ion substitution experiments revealed that the effect of theophylline was Na+- and HCO3(-)-dependent and that these ions were required in the bathing solution. 5. These results with lizard colon are compared with those reported for mammalian colon and the mechanism of theophylline-induced Cl- secretion in these epithelia is discussed.
D000818:Animals; D002712:Chlorides / Q000378:metabolism; D003106:Colon / Q000187:drug effects / Q000502:physiology*; D004553:Electric Conductivity; D005260:Female; D066298:In Vitro Techniques; D007408:Intestinal Absorption / Q000187:drug effects; D007477:Ions; D007700:Kinetics; D008116:Lizards / Q000502:physiology*; D008297:Male; D012964:Sodium / Q000378:metabolism; D013806:Theophylline / Q000494:pharmacology*
D002712:Chlorides; D007477:Ions; D012964:Sodium; D013806:Theophylline