Relationship of the motor activity of the antrum, pylorus, and duodenum to gastric emptying of a solid-liquid mixed meal

The postprandial motor activity of the antrum, pylorus, and duodenum in 15 healthy volunteers was compared with the profiles of emptying of the solid and liquid components of a meal. The liquid component of the meal emptied rapidly in an exponential manner, whereas the solid remained in the fundus of the stomach until ~80% of the liquid had emptied and then emptied in a linear manner. The onset of solid emptying was associated with an increase in the rate of occurrence of antral pressure waves (p < 0.05), and the half-time for solid emptying (t _{1 2} - lag period) was inversely correlated (p < 0.05) with the rate of coordinated contractions involving the antrum. The substitution of 25% dextrose in normal saline as the liquid component of the meal increased the half-time for liquid emptying from a median of 8 to 40 min (p < 0.01), increased the lag period for solid emptying from 40 to 87 min (p < 0.01), and increased the rate of occurrence of isolated pyloric pressure waves during the solid lag phase from 7 to 58/h (p < 0.05), but did not affect the slope of solid emptying or the rate of coordinated contractions involving the antrum during the solid emptying period.