[Effects of theophylline on ion transport in rabbit tracheal epithelium].
Theophylline has several mechanisms of action, including bronchodilation and anti-inflammatory effects that have found use in the treatment of bronchial asthma. However, theophylline's effects at the cellular level have not been fully elucidated. We examined the influence of theophylline on ion transport in the tracheal epithelium of rabbits. To measure ion transport, we used the voltage clamp method. When theophylline was applied to the submucosal side of tissue specimens, no remarkable change in short circuit current (Isc) was noted: however, Isc increased in a dose-dependent manner when theophylline was administered to the mucosal side. Although pretreatment with a Cl channel blocker (diphenylamine 2-carboxylate) suppressed theophylline-induced increases in Isc, a Na channel blocker (amiloride) and Ca-dependent Cl channel blocker (4,4-diisthiocyanatosilbene-2, 2-disultonic acid) did not alter the Isc response to theophylline. These results suggest that theophylline influences tracheal water flow by stimulating the c-AMP dependent Cl channel and inducing Cl secretion.
Ichimura
K
K
First Department of Internal Medicine, Nihon University School of Medicine, 30-1 Ohyaguchi-kamimachi, Itabashi-ku, Tokyo 173-0032, Japan.
Majima
T
T
Horie
T
T
D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology*; D001993:Bronchodilator Agents / Q000494:pharmacology*; D004848:Epithelium / Q000187:drug effects / Q000378:metabolism; D066298:In Vitro Techniques; D017136:Ion Transport / Q000187:drug effects; D008297:Male; D011817:Rabbits; D013806:Theophylline / Q000494:pharmacology*; D014132:Trachea / Q000187:drug effects* / Q000378:metabolism*
D000893:Anti-Inflammatory Agents; D001993:Bronchodilator Agents; D013806:Theophylline