The effects of rabeprazole on parietal cells and enterochromaffin-like cells in rats: a comparison with omeprazole

Background

We investigated the effects of rabe-prazole compared with those of omeprazole on enterochromaffin-like cells and parietal cells in rats. Methods. Rabeprazole or omeprazole was administered for 7 days by intraperitoneal injection (100 mg/kg or 20 mg/kg once a day) and the serum gastrin concentration, the antral density of G cells and D cells, fundic histamine content, fundic H⁺, K⁺-ATPase mRNA level, and parietal cell morphology were determined. Results. Both rabeprazole and omeprazole inhibited gastric acid secretion and increased the intragastric pH to over 6.5, as well as causing a marked increase in the serum gastrin concentration. The serum gastrin level was lower with rabeprazole treatment than with omeprazole treatment at both doses. Also, the antral G-cell density was higher with omeprazole than with rabeprazole, while the increase in both the histamine content and the H⁺, K⁺-ATPase mRNA level in the fundic mucosa was higher with omeprazole treatment at both doses, with the difference being significant at 100 mg/kg. Ultrastructural examination indicated that the stimulation of parietal cells by omeprazole was stronger than that by rabeprazole. Conclusions. Rabeprazole treatment does not drive enterochromaffin-like cells and parietal cells as strongly as omeprazole treatment despite its potent acid suppressive effect, suggesting that it represents a new generation of proton pump inhibitors.