Co-localization of nitric oxide synthase, neuropeptides and tyrosine hydroxylase in nerves supplying the human post-natal vas deferens and seminal vesicle.

Abstract

To determine the distribution and patterns of co-localization of nitric oxide synthase (NOS), neuropeptides and tyrosine hydroxylase (TH) in intrinsic nerves of the human post-natal vas deferens and seminal vesicle. Double and triple immunolabelling methods were used in tissue from 10 male infants and children (age range 2 months to 3 years) obtained at post-mortem examinations carried out within 12 h of death. Most nerves supplying the muscle coat of either organ were TH-immunoreactive (-IR), most of which also contained neuropeptide Y (NPY) while a smaller proportion contained both NPY and NOS. Minor populations of the TH/NPY-IR intramuscular nerves contained calcitonin gene-related peptide (CGRP), galanin (GAL), met-enkephalin (m-ENK) or vasoactive intestinal polypeptide (VIP). Non-TH-IR intramuscular nerves were relatively infrequent and most contained NPY and either VIP or NOS. Presumptive secretomotor nerves formed subepithelial plexuses in both organs, most of which contained NPY co-localized with either VIP or NOS, with minor populations containing CGRP and/or GAL. TH- and substance P (SP) -IR nerves were not observed subepithelially. Perivascular nerve plexuses were mainly formed by TH-IR varicose nerves, most of which contained co-localized NPY and CGRP, with a smaller proportion containing NPY and NOS and minor populations containing VIP, m-ENK, SP or GAL. These results indicate that the autonomic control of the human vas deferens and seminal vesicle is provided by several immunohistochemically distinct nerve populations. Furthermore, NOS is present in a proportion of both the noradrenergic and non-noradrenergic nerves. Pharmacological studies are now required to elucidate the precise roles of nitric oxide and neuropeptides in the functional control of these organs.