Distribution patterns of vasoactive intestinal peptide and NPY in the lumbar-sacral sympathetic chain ganglia of pigs.

摘要

The aim of this study was to determine the existence and coexistence patterns of vasoactive intestinal peptide (VIP) and neuropeptide Y (NPY) in neurons and nerve fibres of the porcine lumbosacral sympathetic chain ganglia. The studied ganglia were fixed with 4% buffered paraformaldehyde (perfusion) and then labelled by means of double-immunofluorescence using a mixture of antibodies cultivated in different species. The highest number of NPY-positive cells was observed in the lumbar ganglia and diminished in the direction of the caudal part, where only single neurons were observed. In contrast, a different pattern of distribution was observed for VIP-positive neurons, whose number was higher in the more caudally located ganglia. Two populations of VIP-positive neurons could be distinguished: single, showing strong immunofluorescence and often with visible processes, located in the central part of the ganglia; and a second population, composed of clusters of 4-8 cells and often colocalizing NPY. VIP-positive nerve fibres surrounded both NPY+ neurons and neurons lacking either NPY and/or VIP. The presence of a small number of NPY-positive neurons exhibiting very weak immunofluorescence in the more caudally located SChG suggested a switch of neuromediators produced there. An increase in the percentage of non-noradrenergic sympathetic neurons in the more caudally located SChG might be implicative for a specific innervation pattern of target tissues of these ganglia..