Secretion of Gastric Hydrochloric Acid and Sialic Acid during Administration of Acetylsalicylic Acid: An Experimental Study in Rats with Chronic Gastric Fistula

Abstract

It is a well known fact that orally administered acetylsalicylic acid causes a high incidence of gastric side effects (from mild gastritis to ulcer). The mechanism for the development of the side effects is still a matter of dispute. In the present study rats were operated and chronic gastric fistulas were performed. This permitted regular collection of gastric juice. The test compound was administered directly into the stomach as pure acetylsalicylic acid or in enteric coated preparation (Premaspin®) which only permitted liberation of the active principle in the alcaline milieu of the duodenum. In addition, deposition of the drug was also made through a tube into the duodenum. The gastric juice was analysed for its variations in HCl concentration. Similar determination of total and free sialic acid was taken as an indication of changes or destruction of the mucoid component. If the drug was liberated in the duodenum or directly placed there or if a small amount of the pure acetylsalicylic acid was administered in the stomach minimal changes were recorded in the parameters used as compared to controls. A high dose of the drug intragastrically appeared to cause an immediate increase of the mucous content followed by a mucous production with a low content of sialic acid and an increased fraction of free sialic acid. This could be due to an increased break down of the mucus or defect mucous production. The results indicate that reduced side effects of acetylsalicylic acid are to be expected if the gastric mucosa is protected from direct contact with the compound.