Ultrastructural evidence for adrenergic and cholinergic innervation of the human ureter

Electron microscopic study of the autonomic innervation of the human ureter demonstrated the existence of adrenergic and cholinergic nerve terminals. The 2 types of nerves were observed in the adventitia, smooth muscle layer and submucosa. The presence of adrenergic and cholinergic nerves was confirmed with the aid of 5-hydroxydopamine, a false sympathetic neurotransmitter that may be used as a specific marker for adrenergic nerve endings at the ultrastructural level. Adrenergic and cholinergic nerves were observed to run in close contact with each other in the same nerve fiber, providing ultramorphological evidence for a possible interaction between the 2 components of the autonomic nervous system in the human ureter.