Immunohistochemical evidence for the presence of a Vasoactive Intestinal Peptide, Neuropeptide Y, and Substance P, in rat adrenal cortex after acute heat stress

Immunohistochemistry revealed the presence of Vasoactive Intestinal Peptide (VIP), Neuropeptide Y (NPY), and the absence of Substance P (SP) immunoreactivity in the rat adrenal cortex. VIP- and NPY-immunoreactivity were detected in nerve fibers around the small blood vessels projecting into the capsule and cortical zones surrounding blood vessels and cortical cells. After acute heat stress, VIP- and NPY-immunoreactivities in the nerve fibers were reduced, probably as a result of the release of these peptides.