Immunohistochemical localization of neuropeptides in nerve fibers of the porcine vagina and uterine cervix.

The distribution of vasoactive intestinal polypeptide, substance P, Met5-enkephalin-Arg6-Gly7-Leu8, neuropeptide Y, calcitonin gene-related peptide and bombesin/gastrin releasing peptide was studied immunohistochemically in nerve fibres supplying the vagina and uterine cervix of sexually immature pigs. Nerves containing neuropeptide Y- and Met5-enkephalin-Arg6-Gly7-Leu8-immunoreactivity were particularly numerous in the uterine cervix and vagina. Vasoactive intestinal polypeptide- and and calcitonin gene-related peptide-containing nerves were less numerous, whereas the bombesin/gastrin releasing peptide- and substance P-immunoreactive nerves were scarce in these organs. Generally, the immunoreactive fibres, nerve networks or bundles were distributed under the serous membrane, among smooth muscle of muscular membranes, in the submucosal layer and under the luminar epithelium of the uterine cervix and vagina.