Immunohistochemical Study on the Innervation of the Chicken Harderian Gland by Peptides (Galanin, PACAP27 and PACAP38)-containing Nerves.

Abstract

Localization of neuropeptides (galanin, PACAP 27 and 38) was investigated in the chicken Harderian gland by immunohistochemistry. Immunoreactivity for three peptides examined in this study was detected on nerve elements in the pterygopalatine ganglion and the gland. Pterygopalatine ganglion contained nerve cell bodies showing immunoreactivity for galanin, PACAP 27 and 38. Dot-form immunoreactivity for PACAPs was also detected around immunonegative nerve cell bodies. Galanin immunoreactivity was observed on larger nerve cell bodies and those were most commonly observed in the ganglion. Nerve fibers showing immunoreactivity for the neuropeptides were distributed in the interstitial tissue of the Harderian gland. Fine immunoreactive nerve fibers were found running beneath the capsule and between acini. No im-munoreactive nerve fibers were found contacting with epithelial cells of the collecting duct. The present data suggested that nerves containing galanin and PACAPs have a relation to the regulation of the immune function of the chicken Harderian gland.