Peptidergic nerves in the ureter

Vasoactive intestinal peptide (VIP) and substance P were demonstrated in the pig ureter by immunohistochemical techniques. Nerves containing these materials were related mainly to the smooth muscle layer in the normal and obstructed ureter. In isolated ureteral segments, VIP caused relaxation at doses exceeding 0.18 micrograms/ml, with no significant difference seen in the effect on normal and obstructed ureter. Vasoactive intestinal polypeptide may play a role in the regulation of ureteral smooth muscle tone.