Immunohistochemical localization of neuropeptides in the porcine thoraco-lumbar paravertebral ganglia.

The existence and distribution pattern of neuropeptide Y, Met5-enkephalin-Arg6-Gly7-Leu8, vasoactive intestinal polypeptide, calcitonin gene-related peptide, substance P and bombesin/gastrin releasing peptide in the neuronal elements of the thoracolumbar paravertebral ganglia (T4-L6) were studied immunohistochemically in sexually immature female pigs. Subpopulations of nerve cell bodies containing immunoreactivity to neuropeptide Y, Met5-enkephalin-Arg6-Gly7-Leu8, vasoactive intestinal polypeptide and calcitonin gene-related peptide were described. However, neurons were non-immunoreactive for substance P and bombesin/gastrin releasing peptide. The solitary small intensely fluorescent cells contain calcitonin gene-related peptide-, substance P- and Met5-enkephalin-Arg6-Gly7-Leu8-, whereas the some cells in clusters contained only substance P and only substance P and Met5-enkephalin-Arg6-Gly7-Leu8. Immunoreactivities to all studied peptides occurred in the nerve fibres within investigated ganglia. Additionally the number of nerve fibres containing particular peptides as well as their distribution pattern were found to vary. The results of this study were compared with those of previous investigations in other species.