Uncharted cholinergic nerves in the rabbit parotid gland.

Cholinergic nerves are shown to be left in the rabbit parotid gland after avulsion of the auriculo-temporal nerve: a cholinesterase inhibitor injected through the duct caused secretion, thereby revealing leakage of acetylcholine from cholinergic nerve endings, and acetylcholinesterase positive nerves were found histochemically. The incomplete cholinergic denervation offers an explanation to the fact that some choline acetyltransferase activity remains in the 'denervated' glands.