Binding sites for calcitonin gene-related peptide in regenerating gastric mucosa

To clarify the effector sites and significance of calcitonin gene-related peptide (CGRP) in the gastric mucosa, the specific binding sites of CGRP in the rat stomach were studied with autoradiography of soluble compounds and in vitro autoradiography. Binding sites for CGRP in the stomach were seen on the vascular smooth-muscle cells of the arterioles and venules, on the nonvascular smooth-muscle cells of the muscularis mucosae, and on the longitudinal layer of the muscularis propriae. After acetic acid treatment, the number of silver grains was significantly increased in the regenerated mucosa. These data support the significant role of CGRP in the regulation of cytoprotection of the stomach through an increase in the microcirculatory blood flow and through extended smooth-muscle relaxation.