THE STRUCTURE AND AUTONOMIC INNERVATION OF THE VESICOURETERAL JUNCTION IN CASES OF PRIMARY URETERAL REFLUX

Objective To determine the histological structure and autonomic innerv ation of the vesico-ureteric junction (VUJ) in cases of primary ureter ic reflux, to compare the results with those reported previously for n on-refluxing VUJs and thus determine possible structural anomalies whi ch could be responsible for vesicoureteric reflux (VUR). Materials and methods Nineteen specimens of VUJs with reflux were obtained from fou r males and 10 females undergoing ureteric reimplantation. Serial froz en sections were cut and stained either with Masson's trichrome or imm unostained for protein gene product (PGP 9.5), a general nerve marker, dopamine beta hydroxylase (D beta H), a marker for noradrenergic nerv es, or neuropeptide Y (NPY). Results Longitudinally orientated muscle bundles of narrow diameter accompanied the ureter to its termination a t the ureteric orifice, where they merged with those of the superficia l trigone. In some specimens, an additional muscle component was ident ified, situated on the outer aspect of the ureteric muscle coat, consi sting of an incomplete layer of distinctive muscle whose constituent c ells formed an interlacing meshwork. Occasionally, specimens included detrusor muscle which consisted of relatively large diameter compact b undles separated from the ureter by a connective tissue sheath. D beta H- and NPY-immunoreactive (-IR) nerves were numerous among the ureter ic muscle bundles. Many NPY-IR nerves occurred within the detrusor mus cle while D beta H-IR nerves were mainly perivascular. When present, t he outer muscle component was richly innervated by both D beta H- and NPY-IR nerves. PGP immunoreactivity varied among regions in the same s ection, PGP-IR nerves frequently being less numerous than those contai ning D beta H or NPY, Conclusion These results indicate that the morph ology of the VUJ in cases of VUR is indistinguishable from the normal VUJ described previously, Furthermore, the density and distribution of D beta H-and NPY-IR nerves is identical to that in controls, However, the antigenicity of PGP in the reflux specimens appears to be masked in some regions by an unknown factor.