Neuro-insular complexes (neural elements in juxtaposition to islet cells of the pancreas) were studied in Holtzman albino rats.
Pancreases were stained by either the aldehyde-fuchsin-ponceau (A-F-P) or the acetylcholinesterase (ACHE) technique. The A-F-P stain gave good definition of islet structure. Although some nerve cell bodies were distinguishable with this stain, the AChE technique gave better definition of nerve cells, including interstitial cells of Cajal.
In adult rats every islet examined had a nerve network. In newborns the nerve network was less apparent though some nerve elements were present. A nerve network typical of the adult was found in rats 48 hours after birth.
Following insulin and glucose loading, variation in the localization of AChE was noted. It is suggested that neuro-insular complexes have a modulatory influence on release of hormones.