Acid in the duodenum.

Acid in the duodenum triggers many physiological responses. Also, acid in the duodenum elicits hyperalgesia of the foregut. In the article by Hobson et al. in this issue the reduction of the latencies in evoked potential in response to electrical stimulation of the esophagus after duodenal acidification is reported, which may explain the symptom development in functional dyspepsia. Microscopic damages of the duodenal epithelium might be responsible for such changes. Microscopic damages of the intestinal epithelium may come into the center stage of the pathogenesis of functional GI disorders.