Generation of dyspeptic symptoms by direct acid infusion into the stomach of healthy Japanese subjects.

Objective: The relationship between acid and dyspeptic symptoms has not been fully understood.
Aim: To investigate the type and severity of dyspeptic symptoms induced by direct acid infusion into the stomach of Japanese healthy subjects.
Methods: This was a multi-centre, cross-over, randomized, double-blind study in 27 healthy subjects (mean age 27). Each fasted subject received two tests with 150 mL of 0.1 mol/L hydrochloric acid infusion (15 mL/min for 10 min) and the same volume of pure water infusion. The type and severity of symptoms were assessed by a 10 cm visual analogue scale administered every 2 min up to 30 min.
Results: Various symptoms were reported after both acid and water infusions. Most of the symptoms were more severe after acid infusion compared with water infusion (acid vs. water: discomfort 1.8 +/- 0.4 vs. 0.5 +/- 0.1, pain 0.6 +/- 0.3 vs. 0.1 +/- 0.1, reflux 1.0 +/- 0.3 vs. 0.3 +/- 0.1 and satiety 1.1 +/- 0.4 vs. 0.2 +/- 0.1). The area under curve for dysmotility like symptoms (heavy feeling in the stomach, bloating, nausea or feeling sick, and belching) was significantly higher in acid infusion, and symptoms continued after infusion of the acid.
Conclusion: Acid induced into stomach induced dysmotility-like predominant dyspeptic symptoms in Japanese healthy control subjects, demonstrating the possible importance of acid in symptom generation.