NITROXERGIC INNERVATION OF THE HUMAN URETEROVESICAL JUNCTION

Nitric oxide synthase (NOS) immunohistochemistry and nicotinamide aden ine dinucleotide phosphate diaphorase (NADPH-d) histochemistry were us ed to investigate the distribution of nitroxergic, i.e., nitric oxide- synthesizing, neuronal perikarya and processes in the human ureteroves ical junction (UVJ). Tissue specimens obtained from two cadaver kidney donors and two patients undergoing radical cystectomy for bladder can cer were examined. Clusters of NOS-immunoreactive neurons were localiz ed in extramural ureterovesical ganglia. NOS-containing nerve fibers t raveled within large extramural nerve trunks and marched among smooth muscle bundles. Extramural and intramural blood vessels were encircled by varicose NOS-positive axonal processes. The distribution of NOS im munoreactivity paralleled the staining pattern for NADPH-d activity. U rothelium stained strongly for NADPH-d activity but showed no NOS immu nolabeling. Specimens from all four patients investigated showed simil ar staining patterns. Our results suggest that nitric oxide, a potent smooth-muscle-relaxing neurotransmitter in the autonomic nervous syste m, plays a physiologic role in opening the human UVJ.