Peptidergic innervation of the human prostate, seminal vesicle and vas deferens.

Neuropeptidergic innervation of the human prostate, seminal vesicle and vas deferens was investigated by immunohistochemical methods. The innervation pattern of all organs was very dense. Neuropeptide Y- and tyrosine hydroxylase-positive nerve fibers were most abundant and localized mainly in the smooth muscle layer. On the contrary, vasoactive intestinal polypeptide-positive nerve fibers were mainly found beneath the epithelium. Also leu-enkephaline-, peptide histidine isoleusine- and calcitonin gene-related peptide-positive nerve fibers could be observed in all organs, but somatostatin-positive nerves only in the prostate and seminal vesicle and met-enkephalin- and substance P-positive nerves only in the prostate.