RESUMO
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(-3) m, cumulatively) were tested on carbachol-induced (10(-6) m) contraction. In addition, the effects of PPI preincubation (all 10(-3) m) on the contractions induced by cumulative carbachol (10(-9) -10(-5) m), angiotensin-2 (10(-9) -10(-5) m) 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.
