Hypersensitivity of gastric parietal cells to selective H2-receptor stimulation in duodenal ulcer

According to previous studies, duodenal ulcer patients not only secrete more acid than normal subjects, but are also more sensitive to pentagastrin stimulation. The aim of this study was to investigate whether hypersensitivity of parietal cells also occurs with specific H2-receptor agonists such as impromidine. Twelve duodenal ulcer patients and 12 healthy volunteers were admitted to the study. After 30 minutes of basal secretion, impromidine was infused at increasing doses (2.5; 5.0; 10.0; 20 μg/kg-1/h-1) in both groups of subjects. The gastric acid secretion was significantly higher in the duodenal ulcer group. The percentage, for each dose, of the calculated maximal response (CMR) was always higher in the patient group, and the difference, with respect to the control group, was statistically significant. Also, the average D50 was significantly lower in the duodenal ulcer group. Drug safety evaluation confirmed the presence of reversible dose-dependent pharmacological side effects. This study showed that parietal cells are more sensitive to highly selective H2-receptor agonists such as impromidine. These results add further information to the physiopathological features of duodenal ulcer.