Peptidergic (vasoactive intestinal peptide) nerves in the genito-urinary tract

The feline genito-urinary tract receives a rich supply of nerve fibers displaying immuno-reactivity like that of vasoactive intestinal peptide. Nerves containing vasoactive intestinal peptide are particularly numerous in the trigonum area of the bladder, around the ureteral openings and in the upper part of the urethra in both sexes, in the epididymis, prostate and vas deferens, and in the uterine cervix. Ganglia located close to or within the wall of the trigonum area and of the upper urethra contain numerous immunoreactive nerve cell bodies, which may be the origin of the fibers containing vasoactive intestinal peptide that innervate these regions.