Co-localisation of tyrosine hydroxylase, nitric oxide synthase and neuropeptides in neurons of the human postnatal male pelvic ganglia

Abstract

Double-label immunocytochemistry was used to investigate the co-localisation of neuropeptides and the enzyme nitric oxide synthase (NOS) with tyrosine hydroxylase (TH) in autonomic ganglia of the human postnatal male pelvic plexus. Postmortem specimens were obtained from six male infants and children ranging in age from 2 to 12 months who had died as a result of cot death or accidental trauma. On average, ganglia lying adjacent to the neck of the urinary bladder contained 45% of neurons which were TH-immunoreactive (-IR) while ganglia situated adjacent to the posterior and lateral aspects of the prostate gland contained 67% of neurons which were TH-IR. All the TH-IR neurons also contained dopamine /3-hydroxylase and were considered to be noradrenergic in type. On average, 61% of TH-IR neurons in bladder ganglia contained NOS, compared with 77% of non-TH-IR neurons (based on counts of over 1000 cells in each case), while the percentages of TH- and non-TH-IR neurons containing neuropeptides were: calcitonin gene-related peptide (CGRP) (30%; 11 %), neuropeptide Y (NPY) (66%; 92%), somatostatin (SOM) (70%; 29%), substance P (SP) (64%; 46%), vasoactive intestinal polypeptide (VIP) (64%; 83%). The equivalent values for TH- and non-TH-IR neurons in prostatic ganglia were NOS (38%; 59%), CGRP (55%; 18%), NPY (62%; 65%), SOM (14%; 20%), SP (13%; 8%) and VIP (42%; 82%). Varicose nerve fibers within the ganglia were seen forming pericellular arborizations around many of the ganglion cells, the most numerous containing TH-, CGRP-, NPY-, SOM- or VIP-immunoreactivity. Less common were pericellular varicosities containing SP-immunoreactivity while terminals containing NOS were not observed. No correlation could be detected between the peptide contents of the ganglion cells and of the associated pericellular terminals. However, the peptide content of the ganglion cells found in association with the urinary bladder and prostate gland correlates well with the previously documented coexistence of enzymes and neuropeptides in the intrinsic nerve fibers supplying these two regions of the human postnatal male genitourinary system.