title: Peptidergic not monoaminergic fibers profusely innervate the young adult human testis.
abstract: Numerous studies have reported that intratesticular nerves exert important regulatory effects on the functions of the male gonad; however, as yet little is known about their distribution in the young adult human testis. The purpose of this study was to explore whether peptidergic and adrenergic nerves occur in the male gonad of this age, and, if present, to depict their distribution further. Thirty testes were collected from 15 reproductively healthy donors aged 21-32 years. Antibodies against protein gene product 9.5 (PGP 9.5), neuropeptide Y (NPY), C-terminal flanking peptide of NPY (CPON) and vasoactive intestinal peptide (VIP) were employed for immunohistochemical detection of intratesticular peptidergic nerves, and those against dopamine-beta-hydroxylase (DBH) and 5-hydroxytryptamine (5-HT) for monoaminergic ones. The testicular parenchyma exhibited a rich innervation by PGP 9.5-positive fibers, mainly associated with Leydig cell nests, blood vessels, and seminiferous tubules. Numerous NPY- and CPON-immunoreactive (IR) nerves also appeared in the gonads, but the vast majority were confined to blood vessels. A small number of VIP-IR fibers were detected in some arterioles. By contrast, however, no fibers displaying DBH or 5-HT immunoreactivity were observed within the testis. Additionally, expression of PGP-9.5, NPY, CPON, VIP, DBH and 5-HT was found in Leydig cells, PGP 9.5 in spermatogonia, and NPY and CPON in peritubular myoid cells. Our results suggest that the young adult human testis is devoid of monoaminergic nerves but profusely innervated by peptidergic fibers, which may serve as major neuronal regulators for testicular functions at this age.
authors.affiliation: Department of Urology, the First Affiliated Hospital of Xi'an Jiaotong University, Urology Institute of Xi'an Jiaotong University, Xi'an, Shanxi, P. R. China.
authors.forename: Yong-Guang
authors.initials: YG
authors.lastname: Gong
authors.forename: Ming-Ming
authors.initials: MM
authors.lastname: Feng
authors.forename: Xiang-Nong
authors.initials: XN
authors.lastname: Hu
authors.forename: Yi-Qiu
authors.initials: YQ
authors.lastname: Wang
authors.forename: Min
authors.initials: M
authors.lastname: Gu
authors.forename: Wei
authors.initials: W
authors.lastname: Zhang
authors.forename: Ren-Shan
authors.initials: RS
authors.lastname: Ge
mesh_terms: D000320:Adrenergic Fibers / Q000378:metabolism / Q000648:ultrastructure; D000328:Adult; D001160:Arterioles / Q000378:metabolism; D015415:Biomarkers / Q000378:metabolism; D004299:Dopamine beta-Hydroxylase / Q000378:metabolism; D006801:Humans; D008297:Male; D009412:Nerve Fibers / Q000378:metabolism / Q000648:ultrastructure*; D009478:Neuropeptide Y / Q000378:metabolism; D012701:Serotonin / Q000378:metabolism; D013737:Testis / Q000098:blood supply / Q000294:innervation* / Q000378:metabolism; D043222:Ubiquitin Thiolesterase / Q000378:metabolism; D014660:Vasoactive Intestinal Peptide / Q000378:metabolism; D055815:Young Adult
chemical_list: D015415:Biomarkers; D009478:Neuropeptide Y; C482860:UCHL1 protein, human; D012701:Serotonin; D014660:Vasoactive Intestinal Peptide; D004299:Dopamine beta-Hydroxylase; D043222:Ubiquitin Thiolesterase