Effects of acetylsalicylic acid on electromechanical activity ofin vivo rabbit ileum

Aspirin has antisecretory and ulcerogenic properties in the gastrointestinal tract. The aim of this study was to determine the effects of acetylsalicylic acid (ASA) on the electrical and mechanical activity of the ileum in anesthetized New Zealand White rabbits. Ileal electromechanical activity was recorded from serosal electrodes and a miniature intraluminal balloon. Thirty minutes after injection of ASA (30, 60 and 100 mg/kg intravenous) significant and dose-dependent increases in the percentage of slow waves with action potentials were observed when compared with saline-injected animals. The onset of action potentials correlated with phasic increases in intraluminal pressure, indicating the onset of circular muscle contractions. Injection of 15 mg/kg ASA, sodium salicylate (100 mg/kg intravenous) or saline had no effect on baseline action potential activity. Prostaglandin E₂ (PGE₂)(5 and 10 g/kg intravenous) significantly increased slow-wave frequency and decreased ASA-induced action potential activity. This study demonstrates that (1) ASA, but not sodium salicylate, stimulates phasic ileal action potential and contractile activity and (2) in ASA-treated animals, PGE₂produces differential effects on in vivoslow-wave frequency and action potential activity.