Expression and localization of natriuretic peptide receptor types A and C in human stomach

Evidence indicates that ANP regulates gastric acid secretion and motility. Little is known regarding the expression and function of ANP receptors in the human stomach. The aim of this study was to examine the expression and localization of NPRA and NPRC receptors in human stomach. NPRA and NPRC transcripts were detected in antrum and body. Immunoblot results demonstrated a 130 kDa protein corresponding to NPRA and a 66 kDa protein corresponding to NPRC in both regions. NPRA was localized to the cytoplasm and membranes of smooth muscle cells, vascular structures, and a population of mucosal epithelial cells located primarily in the lower third of the mucosal glands. By double‐immunostaining, the pyloric gland cells were identified as somatostatin‐containing D cells and the oxyntic gland cells identified as both somatostatin‐containing D cells and H,K‐ATPase‐containing parietal cells. A similar localization was demonstrated for immunoreactive NPRC, except that NPRC was not located on parietal cells. We conclude that NPRA and NPRC genes are expressed in normal human gastric antrum and body. Both receptors are expressed in gastric smooth muscle cells as well as somatostatin cells. NPRA receptors are, in addition, expressed on parietal cells. These results suggest a physiologic role for ANP in the regulation of gastric somatostatin and acid secretion as well as motility in the human stomach.