Gastric and pancreatic response to acid in the duodenum after partial duodenectomy

Regulation of gastric acid secretion by secretin and serotonin

We have tested the interaction between serotonin and secretin in pentagastrin-induced gastric acid secretion in six dogs prepared with Thomas gastric and duodenal cannulas. We further examined the effect of methysergide, a serotonin antagonist, on gastric acid secretion. The intravenous administration of serotonin or secretin alone significantly inhibited pentagastrin-induced gastric acid secretion. The combined administration of serotonin and secretin inhibited gastric acid secretion to a greater magnitude than either secretagogue alone. The administration of methysergide diminished basal concentrations of secretin on gastric acid secretion. Methysergide also enhanced the stimulatory activity of pentagastrin-induced gastric acid secretion. The inhibitory action of intraduodenal acidification of pentagastrin-induced gastric acid secretion was reversed by methysergide.

Modification of the gastric secretory response to sham feeding by acidification of the antrum and the duodenum in dogs

The effect of closure of a gastric cannula on the acid response to sham feeding was studied in Pavlov-pouch dogs with intact antro-duodenal regions as well as in antrectomized dogs with gastroduodenostomies. In the latter dogs, the sham feeding response was augmented by infusions of low doses of exogenous gastrin. The acid output after sham feeding in intact dogs was reduced on average by 59% by closure of the gastric cannula. In antrectomized dogs receiving a back-ground stimulation with gastrin, the response to ham feeding was not inhibited by closure of the cannula. The results suggest that the observed hypersecretory response to sham feeding after diversion of gastric acid from antrum and duodenum is mainly due to inactivation of antral inhibitory mechanisms. The pepsin secretion following sham feeding was not consistently changed by closure of the gastric cannula.