Proton pump inhibitors omeprazole, lansoprazole and pantoprazole induce relaxation in the rat lower oesophageal sphincter

Objectives We aimed to investigate effects of the proton pump inhibitors (PPIs) omeprazole, lansoprazole and pantoprazole, which are currently used for the treatment of hyperacidity and gastro‐oesophageal reflux, on the reactivity of the isolated rat lower oesophageal sphincter. Methods Omeprazole, lansoprazole and pantoprazole (all 10–9–10–3m, cumulatively) were tested on carbachol‐induced (10–6m) contraction. In addition, the effects of PPI preincubation (all 10–3m) on the contractions induced by cumulative carbachol (10−9–10−5m), angiotensin‐2 (10−9–10–5m) or electrical field stimulation (EFS; 40 V, 32 Hz, 1 ms, 10 s) were assessed. Finally, the effects of PPI on the spontaneous contractile activity of the tissue were also evaluated. Key findings PPI relaxed precontracted lower oesophageal sphincter in a concentration‐dependent manner and suppressed carbachol‐, angiotensin‐ and EFS‐induced contractions. Furthermore, PPI attenuated spontaneous contractile activity of the tissue. Conclusions Omeprazole, lansoprazole and pantoprazole had a suppressor effect on lower oesophageal sphincter contractions.