Immunocytochemical study of vasopressin-like immunoreactive material in the gastrointestinal tract of the hedgehog Erinanceus europeus

A study was made of portions of the gastrointestinal tract including the stomach, duodenum, jejunum, ileum, colon and rectum, and the hypothalamus of hedgehogs using the peroxidase-antiperoxidase (PAP) method incubating paraffin embedded sections of 6-7 microns thickness in an anti-arginine-vasopressin serum at a dilution of 1:1000. Vasopressin-like immunoreactivity is present in cells of the epithelial layer of the intestinal mucosa ranging from the stomach to the rectum. In the stomach the numbers of these cells are very small although they increase in the small intestine. However, in the different portions of this latter organ no significant differences can be found. Both, in colon and rectum there are cells with vasopressin-like immunoreactive material although at higher concentrations than in the rest of the gastrointestinal (GI) tract. Immunoreactive material is present throughout the epithelial layer of the mucosa and in general the cells of the mucosa are of the open kind. Using the same antiserum and at similar dilution, both cells and nerve fibres containing vasopressin-like immunoreactivity were observed in hypothalamic sections of this animal species and were used as positive controls. It is concluded that in the gastrointestinal (GI) tract of the hedgehog there is a population of epithelial cells that contain a immunoreactivity vasopressin-like-peptide (referred to as vasopressin-like peptide (AV-LP) whose numbers increase in the distal sense