A DOUBLE-LABEL IMMUNOHISTOCHEMICAL STUDY OF INTRAMURAL GANGLIA FROM THE HUMAN MALE URINARY-BLADDER NECK

Double-label immunocytochemistry was used to investigate the colocalis ation of various neuropeptides and the enzymes nitric oxide synthase ( NOS) and tyrosine hydroxylase (TH) in intramural ganglia of the human male urinary bladder neck and trigone. Postmortem specimens were obtai ned from 7 male infants and children ranging in age from 2 mo to 3 y w ho had died as a result of cot death or accidental trauma. On average 60% of the intramural neurons were non-TH-immunoreactive (-IR) (i.e. p resumptive cholinergic) and 40% were TH- and D beta H-IR (i.e. noradre nergic). Within the non-TH-IR population, calcitonin gene-related pept ide (CGRP) was found in 65% of cells, neuropeptide Y (NPY) in 90%, nit ric oxide synthase (NOS) in 45%, somatostatin (SOM) in 90%, and vasoac tive intestinal polypeptide (VIP) in 40%. The corresponding values for the TH-IR neurons were CGRP (54%), NPY (70%), NOS (58%), SOM (73%) an d VIP (40%). All the observed bombesin (BOM)-immunoreactivity was colo calised with TH while 90% of VIP and almost all the CGRP was colocalis ed with NPY. Less than 5% of neurons were immunoreactive for substance P (SP) or met-enkephalin (m-ENK) and some of these also contained TH. Varicose nerve fibres were seen in close proximity to some of the int ramural neurons, the majority of such varicosities showing immunoreact ivity to CGRP, VIP or TH. Less common were pericellular varicosities i mmunoreactive to NPY, SOM or SP. These results demonstrate the neuroch emical heterogeneity of intramural neurons in the human bladder neck a nd provide indirect evidence for the complexity of the peripheral inne rvation of the human urinary bladder.