The innervation of the bovine ductus deferens: comparison of a modified acetylcholinesterase-reaction with immunoreactivities of cholinacetyltransferase and panneuronal markers

Abstract

The innervation pattern of the bovine deferent duct was studied by acetylcholinesterase (AChE)-histochemistry and by immunohistochemical methods. Using antibodies against protein gene product-9.5 (PGP-9.5) and neuron specific enolase (NSE) the complete innervation pattern can be visualized. Thick nerve bundles in the periductal connective tissue supply the two-layered muscular coat. The inner, mainly circularly arranged muscle bundles are innervated by a particularly dense plexus, whereas the nervous network of the more longitudinally running outer musculature is somewhat looser. Additionally, nerve fibres were observed in the subepithelial space in connection with blood vessels and in close proximity to the basal lamina. An innervation pattern analogous to that of the two panneuronal markers was displayed in the immunoreaction against dopamine-beta-hydroxylase (DBH), indicating that the innervation of the bovine deferent duct is predominantly adrenergic. However, the positive reaction with a monoclonal antibody against cholinacetyltransferase (ChAT) specifically demonstrated for the first time the presence of a cholinergic nerve plexus, restricted to the inner muscular layer and the subepithelial space. A modified, direct-colouring AChE-method is presented, which uses copper chloride as source of cupric ions, acetylthiocholine chloride as substrate and 2-morpholinoethanesulphonic acid (MES) as buffer. After short incubation (1-2 h) our modified method allows the specific visualization of cholinergic nerves, comparable to the results of ChAT-immunoreactivity; following a long incubation time (24 h), it reliably illustrates the autonomous innervation pattern as completely as immunohistochemical panneuronal markers.