A new method to measure gastric emptying in conscious dogs: a validity study and effects of EM523 and L-NNA.

A new method for measurement of gastric emptying without the use of radioisotope markers has been developed in dogs. A test meal was given after measurement of its freeze-dried weight, and 1-ml duodenal samples were collected through an indwelling tube at 15-min intervals, and their absolute weight was measured. The duodenum was continuously perfused with phenolsulfonphthalein to determine the recovery of each sample. Three different calorie or fat-enriched meals were administered with 100 ml saline containing polyethylene glycol as a liquid marker. The results showed that increasing the calorie load of, and adding fat to, the test meal proportionally delayed gastric emptying of the solid phase. Utilizing this method, it was found that EM523, an erythromycin derivative, accelerated the gastric emptying of solids, whereas N(omega)-nitro-L-arginine (L-NNA) markedly delayed the gastric emptying of both solids and liquids. In conclusion, this freeze-drying method is a reliable technique for measuring the gastric emptying of the solid phase in dogs.