Histochemical and immunohistochemical studies on intraepithelial nerve fibers in the ejaculatory duct of the monkey (Macaca fuscatus).

Abstract

With special attention to intraepithelial nerve supply, the distribution of peripheral nerve fibers in the ejaculatory duct of the monkey (Macaca fuscatus) was examined by histochemical and immunohistochemical methods and conventional transmission electron microscopic (TEM) method. The conventional TEM study has suggested that there are two types of intraepithelial nerve fibers, i.e. cholinergic and peptidergic. Acetylcholinesterase (AChE)-positive nerve fibers which were seen by means of light microscopy (LM) as surrounding the epithelium were revealed to be present intraepithelially by means of TEM examination. Neuropeptide Y (NPY)-like immunoreactive nerve fibers were richly distributed in the ejaculatory duct with a dense plexus spreading just beneath the epithelium. The immunoreactive nerves appeared, in part, to enter the epithelium. Substance P (SP)- and calcitonin gene-related peptide (CGRP)-like immunoreactive nerve fibers were found to be present to a moderate extent in the ejaculatory duct; some of them entered the interior of the epithelium to extend their nerve terminals to its free surface. Neural elements clearly immunoreactive for tyrosine hydroxylase (TH) and vasoactive intestinal peptide (VIP) could not be found in the ejaculatory duct, except for the surroundings of the blood vessels. Possible functional roles of these intraepithelial nerves were discussed on the basis of their distribution pattern.