The distribution of cholinergic and adrenergic nerves in the mammalian epididymis: a comparative histochemical study.

Abstract

AbstractThe distribution of cholinergic and adrenergic nerves in the epididymis was studied in the dog, cat, rat and rabbit using specific histochemical techniques for acetylcholinesterase and norepinephrine. Both cholinergic and adrenergic nerves are associated with tunical, septal and interstitial blood vessels, run independently in the intertubular connective tissue, and surround the epididymal tubules.Throughout the epididymis there are rich adrenergic and cholinergic perivascular plexuses. The distribution and pattern of interstitial and peritubular cholinergic and adrenergic nerves vary in the three anatomical regions of the epididymis in different animals. In the dog and cat the nerves form plexuses in relation to the ductuli efferentes in the caput, and run as isolated fibers in the corpus epididymidis. In the rat and rabbit there are no interstitial or peritubular nerves in the caput and proximal part of the corpus and few nerves in the distal part of the corpus. The cauda epididymidis is the most richly innervated part of the epididymis. Both interstitial and peritubular cholinergic and adrenergic nerves form plexuses of nerve fibers and bundles, which progressively become more prominent and more intricate as the cauda is traced distally towards its junction with the vas deferens. These changes in innervation pattern follow the distalward increase in thickness of the muscular wall of the ductus epididymidis and are noted in all animals studied.Ganglia are encountered only in the caput epididymidis in the cat. Cholinergic and adrenergic epithelial fibers are present in the caput and cauda but not in the corpus epididymidis. In the cauda they penetrate through most of the thickness of the epithelium; the cholinergic fibers in this region form a loose intra‐epithelial plexus.