Immunolocalization of Cholecystokinin-2 Receptors in Rat Gastric Mucosa

Abstract

Background: Gastrin exerts trophic effects on the gastric mucosa by mechanisms not yet completely elucidated. Our aim was to localize the cholecystokinin-2 (CCK 2 ) receptor in epithelial cells of foetal and adult rat stomachs in order to determine the cell types that are directly affected by gastrin. Methods: Gastric tissue was subjected to indirect double immunofluorescence staining with antiserum against the C-terminal decapeptide of the CCK 2 receptor and antibodies against 5' bromo-2-deoxyuridine, which had been injected into the rats 1 h before they were killed, the acid pump H,K-ATPase, the membranecytoskeletal linker ezrin, pepsin/pepsinogen or histidine decarboxylase. Results: Undifferentiated foetal gastric epithelial cells expressed CCK 2 receptors, whereas stem cells of adult gastric glands did not exhibit immunoreactivity. However, other epithelial cells in the progenitor zone of adult gastric glands did express CCK 2 receptors. Some of these cells were faintly stained for H,K-ATPase; pepsin/pepsinogen was also detected in this region. Parietal cells in the isthmus/pit region of the glands contained ezrin, and some showed weak immunoreactivity for the CCK 2 receptor. As expected, enterochromaffin-like cells also expressed CCK 2 receptors. Conclusion: Our findings are consistent with the hypothesis that a CCK 2 receptor mediates direct effects of gastrin on gastric epithelial cells during both stomach organogenesis and adult life.

• Cck2
• Receptor
• Gastrin
• Immunofluorescence
• Organogenesis
• Progenitor Zone
• Stomach