Identification of neuropeptide y in superior cervical ganglion neurons that project to the oesophagus - A combined immunohistochemical labelling and retrograde tracing study in pigs.

Neuropeptide Y (NPY) is a neuronal active substance taking part in the regulation of gastrointestinal (GI) tract activity. This study used retrograde neuronal tracing and immunofluorescence methods to analyse NPY-positive neurons located in superior cervical ganglion and supplying the cervical oesophagus in the pig. The presence of NPY was observed in 30% of all neurons supplying the part of oesophagus studied. Probably the number of Fast Blue (FB) positive cells depends on the area of the wall injected with FB and the fragment of oesophagus studied. Therefore, the obtained results indicate that the described peptide is an important factor in the extrinsic innervation of this part of the GI tract.