Neostigmine-Induced Postprandial Phasic Contractility in the Proximal Stomach and Dyspepsia-Like Symptoms in Healthy Volunteers

Abstract

In a subset of functional dyspepsia patients, we have recently described the association between unsuppressed postprandial phasic contractions of the proximal stomach and a specific symptom pattern. To better elucidate the role of phasic contractility of the proximal stomach in symptom generation, we aimed at inducing this motility pattern in healthy volunteers and we carefully monitored symptom onset. Eleven healthy volunteers underwent gastric barostat on two separate days. Gastric tone and phasic contractility were evaluated for a 90-minute period. In particular, after 30 min of basal recording, a caloric liquid meal and neostigmine 0.5 mg IV or saline in a double-blind, randomized, crossover protocol were administered. During the measurement, severity of 9 dyspeptic symptoms was evaluated on a visual analog scale. Computer-aided baseline reconstruction allowed us to quantify phasic contractions as a motility index (MI), reflecting the area between signal and baseline normalized over time. Perception of contractions after placebo or neostigmine was evaluated. Moreover, we tested for influence of gastric tone and phasic contractility on symptoms. After neostigmine, gastric accommodation was not different than after placebo (225 +/- 36 vs 206 +/- 76 mL, P= NS). During the first 30-min postprandial period, the MI was significantly higher after neostigmine than after placebo (26.4 +/- 3 vs 21.4 +/- 3, P < 0.001), confirming the induction of unsuppressed postprandial phasic contractions. The postprandial total symptom score was significantly higher after neostigmine compared to saline; several individual postprandial symptom scores were also significantly higher after neostigmine-compared placebo. After neostigmine, a higher percentage of postprandial contractions was perceived compared to placebo. Unsuppressed postprandial phasic contractility of the proximal stomach is a mechanism potentially involved in the pathogenesis of dyspeptic symptoms.