Immunohistochemical study on the distribution of galanin-containing nerves in the chicken pancreas

The distribution of galanin-containing nervous elements in the chicken pancreas was investigated by use of immunohistochemical method. Galanin-immunoreactive nerve fibres formed a perivascular plexus and a dense network in the subepithelial layer of secretory ducts. The muscle layers of secretory ducts were also supplied with galanin-immunoreactive nerve fibres. The exocrine pancreas received a supply of varicose nerve fibres showing galanin immunoreactivity. In the endocrine part, B-islets were innervated by galanin-immunoreactive nerve fibres, whereas A-islets received fewer nervous elements. Double staining combined with the immunofluorescence method for galanin and acetylcholinesterase histochemistry showed at least two types of ganglion cells in the interlobular connective tissue; one showing both acetylcholinesterase activity and galanin immunoreactivity, and the other showing acetylcholinesterase activity only. The present results demonstrate that the chicken pancreas is innervated by galanin-containing nerves of intrinsic origin and suggest that galanin coexists with acetylcholine in the chicken pancreas.