IMMUNOHISTOCHEMICAL CHARACTERISTICS OF NERVE-FIBERS SUPPLYING THE PORCINE VAS-DEFERENS - A COLOCALIZATION STUDY

Double-labelling immunofluorescence was used to investigate the coexis tence of the catecholamine-synthesising enzymes, tyrosine hydroxylase and dopamine-beta-hydroxylase and several neuropeptides including neur opeptide Y, vasoactive intestinal polypeptide, Leu(5)-enkephalin, soma tostatin, calcitonin gene-related peptide and substance P in nerve fib res supplying the vas deferens in juvenile and adult pigs. The study h as revealed three major populations of nerve terminals innervating the organ: (1) noradrenergic fibres; (2) non-noradrenergic (putative chol inergic) fibres containing vasoactive intestinal polypeptide, neuropep tide Y and somatostatin, supplying almost exclusively the lamina propr ia; and (3) non-noradrenergic, presumably sensory fibres, containing c alcitonin gene-related peptide and substance P. The population of nora drenergic nerves can be divided into three subpopulations: a somatosta tin-containing, a Leu(5)-enkephalin-containing and a subpopulation imm unonegative to the peptides investigated, in descending order of magni tude. Coexistence patterns of the substances existing within nerve fib res supplying the vas deferens blood vessels are clearly different fro m those found in nerve fibres innervating the organ wall. The majority of the noradrenergic fibres associated with blood vessels contain neu ropeptide Y only, while non-noradrenergic perivascular lar nerves cont ain predominantly vasoactive intestinal polypeptide. The possibility o f different sources of origin of the particular nerve fibre subpopulat ions supplying the porcine vas deferens and its blood vessels is discu ssed.