Our aims were to investigate, first, the relationship between gastric tone (measured with a barostat) and gastric emptying (measured by radioscintigraphy with and without barostat) and, second, to determine the effect of a symptomatic intragastric pressure increment on gastric emptying. In 16 healthy subjects we quantified simultaneously gastric tone, emptying, and perception at two different intragastric pressure levels: 2 mmHg (low pressure) or 8 mmHg above intra-abdominal pressure (high pressure). At the low intragastric pressure level, ingestion of tbe meal induced an additional expansion in intragastric volume of 285 +/- 50 ml (P < 0.001), which reflected a gastric accommodative relaxation. At the high pressure level, intragastric volume expanded further, but neither low nor high pressure levels had significant effects on solid emptying. Interestingly, low and high pressure levels produced a similar, modest but significant, acceleration of liquid emptying (17 +/- 5 and 17 +/- 4%, respectively). However, although the low pressure was largely unperceived (score 1.0 +/- 0.5; NS), the high pressure level produced significant symptomatic perception (score 2.5 +/- 0.9; P < 0.05 vs. low pressure). We conclude that 1) gastric accommodation to a meal prevents volume-dependent wall tension increments and 2) the stomach adapts to increments in postcibal intragastric pressure by a limited acceleration of liquid emptying, but wall stress triggers a symptomatic alert mechanism.
