HISTOFLUORESCENCE, IMMUNOHISTOCHEMICAL AND ELECTRON MICROSCOPICAL STUDIES ON THE INNERVATION OF BOVINE SEMINAL AND AMPULLARY GLANDS

Samples of seminal and ampullary glands collected from 15 mature healthy bovine bulls were used in this study. The pattern of innervation of the two glands was investigated using a combination of SPG histofluorescence, PGP 9.5 -immunohistochemical and electron microscopical techniques. For fluorescence microscopical examination, cryostat sections (10-25 um thick) were prepared and stained with SPG - technique for detection of pre- and terminal axonal nerve fibers containing positive monoamine transmitters. For immunohistochemical reaction, antibodies against PGP 9.5, as a very sensitive nerve marker, were used. Both glands revealed nearly similar distribution of nerve fibers. In the muscular coat, a dense network of fine nerve fibers was observed in between the muscle fibers. In the submucosa and interlobular connective tissue, thick wavy bundles of nerve fibers were observed. In close position to the basal border of the glandular epithelium, fine nerve terminals were seen arising from the interstitial axonal bundles. These terminals formed a dense nerve plexus around the glandular end-pieces and appeared highly dense in the seminal gland than that in the ampullary gland. Ultrastructural examination of the glandular epithelium-terminal nerve fibers relationship revealed subepithelial bundles of unmylinated nerve fibers. The terminal axonal nerve fibers were embedded either completely within Schwann's cell processes or appeared partially free toward the glandular epithelium. They were separated from the epithelium by a thin layer of extracellular matrix. Within these nerve terminals two types of synaptic vesicles were demonstrated; small agranular vesicles and large granular vesicles containing electron dense core. Nerve terminals that forming a direct neuro-glandular contact with the epithelial cells were not identified.