Peptidergic innervation within the prostate gland and seminal vesicle.

An immunohistochemical study in which antisera against several neuropeptides were used demonstrated the presence of neuropeptide Y(NPY) and vasoactive intestinal polypeptide (VIP) immunoreactivity in nerve fibers in the human prostate gland and seminal vesicle, whereas no immunostaining for substance P and calcitonin gene-related peptide was observed. The peptidergic innervation was found to be generally moderate to low. NPY- and VIP-immunoreactive fibers were localized in the subepithelial connective tissue as well as the smooth muscle layers in both organs, although the peptidergic fiber networks were more prominent in the seminal vesicle. Most NPY-immunoreactive fibers were observed in the musculature of the seminal vesicle. In addition, NPY- and VIP-immunoreactive fibers were demonstrated in the walls of blood vessels. The results of our study suggest that the innervation of the prostate gland and seminal vesicle by various neuroactive peptides may be involved in the autonomic regulation of these organs in adult man, as well as sympathetic and parasympathetic nerve fibers.