AN IMMUNOHISTOCHEMICAL STUDY OF THE INNERVATION OF THE URETEROVESICALJUNCTION IN INFANCY AND CHILDHOOD

Objective To use histological and immunohistochemical methods to study the structure and innervation of the human ureterovesical junction (U VJ). Materials and methods A series of 24 post-natal specimens taken f rom patients ranging in age from 1 month to 6 years were examined. Rou tine histological slides were stained with Masson's trichrome. In addi tion, an indirect immunohistochemical method was used to study the occ urrence and distribution of nerves immunoreactive for the neuropeptide s vasoactive intestinal polypeptide (VIP), neuropeptide Y (NPY), subst ance P (SP) and calcitonin gene-related peptide (CGRP). Immunoreactivi ty to tyrosine hydroxylase (TH), dopamine-B-hydroxylase (DBH) and to p rotein gene product (PGP) 9.5, a general nerve marker, were also studi ed. Results The UVJ comprised a ureteric muscle component (the intramu ral meter) and a detrusor component (the immediately adjacent region o f the urinary bladder). In the majority of specimens a third or interm ediate layer was also present. This additional component consisted of tightly-packed smooth muscle cells which formed an incomplete layer th at partially surrounded the juxtavesical and intramural parts of the u reter. Numerous PGP-, VIP-, NPY, DBH- and TH- like immunoreactive (-LI R) nerves were associated with the smooth muscle bundles which compris ed the intramural ureter. Such nerves ran in the connective tissue sep arating ureteric smooth muscle bundles and rarely coursed amongst indi vidual smooth muscle cells comprising each bundle. SP- and CGRP- conta ining nerves were rarely observed in association with the intramural u reter and none were detected in the ureteric submucosa. The intermedia te muscle layer was richly innervated by PGP-, TH-, DBH- and NPY- cont aining nerves which ran amongst the smooth muscle cells comprising thi s layer. VIP-, SP- and CGRP-LIR nerves were not observed within the in termediate layer. The detrusor component of the UVJ was innervated by PGP-, NPY- and VIP-LIR nerves which frequently extended between the sm ooth muscle cells forming the detrusor muscle bundles. TH-, DBH-, SP- and CGRP-LIR nerve fibres were rarely encountered. Conclusion These fi ndings indicate that noradrenergic nerves play a major role in the con trol of the ureteric component of the UVJ. In addition, the present re sults form baseline morphological data with which to compare the resul ts of future studies on the structure of the UVJ in cases of vesicoure teric reflux.