Induction of Anacidity Restores Gastric Aminopyrine Clearance in Canine Hemorrhagic Shock

Abstract

The determinants of gastric aminopyrine clearance were studied in a canine hemorrhagic shock model. Adult mongrel dogs were anesthetized, and their stomachs perfused with 0.1 N HCl through an esophageal and a duodenal cannula. Blood flow to the serosal layer of the anterior gastric wall was measured by a laser flowmeter. Hemorrhagic shock was induced by controlled arterial bleeding to a mean systolic blood pressure of 40 ± 5 mm Hg (n = 8), resulting in a 36 ± 8% drop of gastric wall blood flow. In contrast, the aminopyrine clearance did not reveal the expected drop and remained unchanged during shock. When acid secretion was abolished by intravenous omeprazole (1.3 mg/kg bolus plus 0.75 mg/kg/h infusion), aminopyrine concentrations dropped in the gastric perfusate and rose in the serum during shock, resulting in a similar decrease in the clearance (53 ± 25 %) as compared to the flowmeter readings. In control experiments without hemorrhagic shock, omeprazole did not affect the concentrations of aminopyrine in serum and in the perfusate, or the recovery of ¹⁴C-labeled aminopyrine in the mucosa at the end of the experiment. These studies indicate that the aminopyrine clearance is impaired in hemorrhagic shock, and that complete inhibition of acid secretion by omeprazole restores the apparent aminopyrine clearance by divergent effects on blood and gastric juice concentrations of aminopyrine.