Relation between postprandial gastric emptying and cutaneous electrogastrogram in primates

The relation between the cutaneous electrogastrogram (EGG) and gastric emptying was investigated in six rhesus monkeys. Gastric emptying was measured using scintigraphy after administration of two 80-ml mixed solid liquid meals (1.5 and 5.0 kcal/kg) tagged with 99mTc-sulfur colloid and 111In-diethylenetriamine pentaacetic acid. Six epigastric bipolar recordings of the EGG were concurrently obtained, digitized, and band-pass filtered. Portions of the signal with motion artifacts were automatically detected and excluded using two microwave motion sensors. During the early postprandial period, gastric emptying was greater after the 1.5-kcal/kg meal than after the 5-kcal/kg meal, and EGG amplitude increased significantly compared with fasting only after the 1.5-kcal/kg meal. Both emptying and EGG amplitude subsequently decreased after the 1.5-kcal/kg meal, whereas these two parameters increased after the 5-kcal/kg meal. As a result, EGG amplitude was significantly correlated with gastric emptying of solids in all six animals. In contrast, EGG frequency was not significantly different between the two meals and was not correlated with emptying. These results indicate that both the EGG and gastric emptying are modified differently by meals with different caloric contents and that the EGG may represent a useful, although indirect, index of gastric emptying.