Peptidergic (VIP) nerves in the pancreas.

Vasoactive intestinal peptide (VIP) was found to occur in nerves in the pancreas of all species examined, as demonstrated by immunohistochemistry. Immunoreactive nerve terminals were seen to run in the stroma, around acini, and in the wall of blood vessels. Clusters of immunoreactive nerve cell bodies were encountered in the parenchyma; in addition other ganglia were densely innervated by VIP nerves. A particularly dense network of VIP nerves accurred in the wall of the main pancreatic duct. The present observations provide the morphological basis for accepting the action of VIP on pancreatic secretion as physiological.