IMMUNOCYTOCHEMICAL STUDY ON THE INNERVATION OF THE CHICKEN PANCREAS BY VASOACTIVE INTESTINAL POLYPEPTIDE (VIP)-CONTAINING NERVES

Ultrastructural localization of vasoactive intestinal polypeptide (VIP ) was studied in the chicken pancreas by the immunocytochemical method . VIP-immunoreactive nerve endings were found in contact with acinar c ells in the pericapillary space or between acinar cells. They also ter minated on epithelial cells of arteriolae. In pancreatic islets, VIP-i mmunoreactive nerve endings were in contact with B-cells, but not with A- or D-cells. VIP-immunoreactive terminals contained many small clea r vesicles which indicate the cholinergic feature. Nerve endings conta ining many small clear vesicles but not showing VIP-immunoreactivity w ere also detected in both the exocrine and endocrine pancreas. Accordi ng to these data and the previous studies concerning the cholinergic a nd VIPergic innervation of the chicken pancreas, it is suggested that VIP-containing cholinergic nerves innervate B-cells and cholinergic ne rves not containing VIP innervate D-cell.