Effect of intravenous amino acids on the canine gastric mucosa

A mixture of synthetic L-amino acids (Aminoplex 14) was infused intravenously over 4 hours in five dogs each prepared with a gastric fistula and a denervated fundic pouch. Acid and pepsin outputs from the innervated fundic pouch. Acid and pepsin outputs from the innervated gastric mucosa (gastric fistula) increased significantly after 90 minutes' infusion of amino acid. Acid output from the denervated fundic mucosa (Heidenhain pouch) was estimated by a method of intragastric titration and increased significantly only in response to intravenous amino acid infusion when the pouch was subjected to distention with 100 ml of perfusate. Blood glucose, serum gastrin, hematocrit and serum osmolality levels did not change throughout the experiments. Bolus intravenous injection of either atropine (0.15 mg/kg) or cimetidine (10 mg/kg) blocked the acid secretory response to intravenous amino acids. It is concluded that intravenous amino acids stimulate the innervated gastric mucosa to secrete both acid and pepsin. The secretory response from denervated mucosa in only obtained in the presence of fundic pouch distention. The gastric secretory response is susceptible to both atropine and histamine H2 antagonist blockade.