Immunoreactive avian pancreatic polypeptide in the chicken retina: overall distribution

The distribution of avian pancreatic polypeptide (APP)-like immunoreactivity (APP-IR) in the chicken retina was investigated by means of immunohistochemistry. The observation from frozen sections showed that APP-IR is localized in the stratified amacrine cells of the first sublayer. Examination of whole-mounts revealed that APP-IR fibers from a dense fiber plexus at the peripheral margin area and peripheral portion of the retina where they run circumferentially. APP-IR neurons are located in the peripheral portion. From the three-dimensional profiles, APP-IR amacrine cells could be divided into two types.