The Effect of Helicobacter pylori on Gastric Acid Secretion by Isolated Parietal Cells from a Guinea Pig Association with Production of Vacuolating Toxin by H. pylori

Background: One of the features of Helicobacter pylori infection in the human stomach seems to be disordered gastric acid secretion. The effect of vacuolating toxin (VT) produced by H. pylori on gastric acid secretion was examined. Methods: VT(+) (toxigenic) and VT(-) (nontoxigenic) strains of H. pylori were cultured in brucella broth. The culture supernatant was added to isolated parietal cells, and acid secretion and intracellular adenosine 3‘5’-cyclic phosphate (cAMP) and Ca2+ levels were measured with the 14C-aminopyrine (14C-AP) method, with 125I radioimmunoassay (RIA), and with the fura-2 fluorescence method, respectively. Results: In the VT(+) strain a considerable inhibitory effect on 14C-AP accumulation was observed. However, the VT(-) strain had no significant effect in this respect. In the analysis for second messengers the VT(+) strain had no significant effect on intracellular c-AMP and Ca2+. Conclusions: The VT(+) strain of H. pylori has an inhibitory effect on gastric acid secretion, wherea...