Distribution of tyrosine hydroxylase(TH)-like, neuropeptide Y(NPY)-like immunoreactive and acetylcholinesterase(AChE)-positive nerve fibers in the prostate gland of the monkey (macacus fuscatus).

Abstract

Nerve fibers containing immunoreactivities for tyrosine hydroxylase (TH) and neuropeptide Y (NPY), and exhibiting acetylcholinesterase (AChE) reactivity were examined by means of histochemical and immunohistochemical methods in the caudal lobe of the prostate in the monkey, Macacus fuscatus. TH-like immunoreactive nerve fibers were distributed abundantly in the interstitium where smooth muscle fiber bundles were rich and scarcely in the paraurethral region where they were rare. NPY-like immunoreactive nerve fibers, less abundant than TH-like immunoreactive nerve fibers, were observed not only in the interstitium but also around the prostatic acini. AChE-positive nerve fibers were much denser around the acini than in the interstitium. Both the NPY-like immunoreactive and the AChE-positive nerve fibers showed an intimate spatial association with the epithelium of the acini. Judging from the distribution pattern of these nerve fibers, the following assumption is possible. Secretion of the prostatic gland as well as the outflow of the prostatic fluid into the urethra induced by contraction of the smooth muscle cells in the interstitium may be controlled by sympathetic adrenergic nerves, while cellular secretion of the acinar epithelium is regulated by parasympathetic cholinergic nerves. The NPY-like immunoreactive nerve fibers around the acini may be non-noradrenergic; they may regulate the cellular secretion by acting on the cholinergic nerves as well as by having a direct effect on the acinar secretory cells.