Quantitative Analysis of Calcitonin Gene-Related Peptide- and Neuropeptide Y-Immunoreactive Nerve Fibers in Mesenteric Blood Vessels of Rats Irradiated with Cobalt-60 Gamma Rays

The effects of⁶⁰ Co γ rays on calcitonin gene-related peptide (CGRP)-immunoreactive nerve fibers and neuropeptide Y (NPY)-immunoreactive nerve fibers were examined in mesenteric blood vessels of rats. Using a free-floating immunostaining streptavidin-biotin peroxidase complex method combined with a nickel-enhancement technique, we found that the distribution pattern of these two peptidergic nerve fibers in superior mesenteric arteries and superior mesenteric veins did not change, while the densities of CGRP-immunoreactive nerve fibers and NPY-immunoreactive nerve fibers in superior mesenteric arteries and veins varied with the time after irradiation. The results suggested that CGRP and NPY may be important in the development and elimination of radiation-induced injury.