Regional Differences in the Innervation of the Human Ureterovesical Junction by Tyrosine Hydroxylase-, Vasoactive Intestinal Peptide- and Neuropeptide Y-Like Immunoreactive Nerves

Abstract

We have used double-label immunohistochemistry to examine the presence and pattern of colocalization of vasoactive intestinal peptide (VIP), neuropeptide Y (NPY), tyrosine hydroxylase (TH) and protein gene product (PGP) in nerve fibers supplying the human ureterovesical junction (UVJ). Several populations of nerve fibers within the UVJ region were identified according to their expression of potential transmitter substances. Presumptive noradrenergic axons containing TH- and NPY-like immunoreactivity (LIR) and non-noradrenergic fibers containing VIP-and NPY-LIR accounted for most of the total (PGP-LIR) innervation and supplied all regions of the UVJ. The distal ureter, Waldeyer's sheath and the trigone were supplied by predominantly noradrenergic TH/NPY-LIR nerve fibers, whereas the majority of fibers supplying the detrusor muscle were non-noradrenergic VIP/NPY-LIR axons. The similarity in innervation of Waldeyer's sheath, ureter and trigone is consistent with the notion that these structures are all derived from a common mesodermal origin. Regional differences in innervation were also noted within the musculature of the distal ureter: TH/NPY-LIR fibers were localized to the outer part of the ureter, while VIP/NPY-LIR fibers supplied the inner part. This finding suggests that the different layers of the ureter may be independently controlled by different populations of nerves. The findings of this study support the view that noradrenergic nerves are important in maintaining the tone of the UVJ, but indicate that other neurotransmitters or neuromodulators may also be involved in the control of this region.