NEURONS OF THE PELVIC PLEXUS OF THE MALE PIG - DISTRIBUTION AND IMMUNOHISTOCHEMICAL CHARACTERISATION WITH SPECIAL EMPHASIS ON NEURONS SUPPLYING THE VAS DEFERENS

摘要

This paper deals with the distribution and immunohistochemical characteristics of neurons in the pelvic plexus of the juvenile male pig. The arrangement and neurochemical coding of pelvic neurons supplying the vas deferens are also described. The investigations revealed the presence of a larger ganglion (called the anterior pelvic ganglion, GPA) in the angle between the urethral end of the vas deferens and the cranial end of the seminal vesicle. The remaining pelvic neurons were located caudally andclustered in ganglia which altogether formed a compact, but complex structure. The structure consisted of left and right stripes of ganglia distributed on and along lateral sides of the pelvic part of the urogenital duct. The stripes occupied the anglesbetween the laterally protruding parts of the seminal vesicles and bulbourethral glands, and the urogenital duct. The stripes were interconnected with transversal, horse shoe-shaped bands (3-5) of ganglia which ran on the upper surface of the urogenitalduct under the accessory genital glands. By means of the retrograde tracing technique using the fluorescent tracer Fast Blue (FB) the pelvic ganglia were found to contain many neurons supplying the vas deferens. FB-positive (FB~+) neurons occurred in both left and right GPAs and other ganglia, however, the majority of them were located ipsilaterally. The immunohistochemistry included single- and double--labelling immunofluorescence, combined sometimes with TSAMD method. Additionally, consecutive sections stained for different substances were compared to investigate the co-localization of the antigens. It has been found that the GPA is a "mixed" ganglion consisting of both adrenergic, containing catecholamine-synthesizing enzymes (tyrosine hydroxylase, TH and dopamine β-hydroxylase, DβH), and roughly the same number of non-adrenergic neurons. The vast majority of FB~+ neurons belonged to the subpopulation of adrenergic neurons. Besides the catecholamine-synthesizing enzymes, pelvic neurons were found to contain some neuropeptides that often co-existed within these nerve cell bodies. Met~5-enkephalin-Arg~6-Gly~7-Leu~8 (MEAGL), neuropeptide Y (NPY), and, to a lesser extent, galanin (GAL) were the peptides most often occurring and co-localizing within adrenergic, including FB~+, neurons. Non-adrenergic neurons, including FB~+ nerve cells, usually contained NPY, vasoactive intestinal polypeptide (VIP) and/or somatostatin (SOM) and, less frequently, calcitonin gene-related peptide (CGRP) Numerous varicose nerve fibres containing both CGRP and substance P (SP) were detected within the ganglia studied. These fibres, however, intensely innervated only adrenergic neurons, thus, also the vast majority of FB-positive nerve cells. Nerve fibres positive to other substances investigated were definitely less numerous and they often supplied both adrenergic and non-adrenergic neurons with single nerve fibres.