EFFECT OF GASTRIN ON ANTRODUODENAL MOTILITY - ROLE OF INTRALUMINAL ACIDITY

The effect of gastrin on the migrating motility complex (MMC) was stud ied in seven healthy subjects. It was hypothesized that a potential ef fect of gastrin on the MMC may result from intraluminal acidification through increased gastric acid secretion. Therefore, antroduodenal man ometry and intraluminal acidity were recorded simultaneously. The effe ct of gastric acid inhibition, with and without administration of gast rin, on antroduodenal motility and intraluminal acidity was also evalu ated and compared with saline infusion (control). Continuous infusion of gastrin-17 (20 pmol.kg(-1).h(-1)) increased intragastric and intrad uodenal acidity and suppressed phase II and phase III motor activity i n both antrum and duodenum. Concomitant gastric acid inhibition with i ntravenous famotidine, as demonstrated by intragastric neutralization of pH, completely antagonized the effect of gastrin on the MMC. In fac t, famotidine infusion, both with and without administration of gastri n, significantly shortened MMC cycle length. It is concluded that the effect of gastrin on interdigestive antroduodenal motility results fro m increased intraluminal acidity.