DISTRIBUTION OF ORPHANIN FQ IN THE RAT - AN IMMUNOHISTOCHEMICAL STUDY

Orphanin FQ (OFQ) is endogenous ligand for an opioid-like-G-protein-co upled receptor. Its distribution in rats has not been demonstrated to date. We have used specific anti-OFQ antiserum to identify OFQ immunoh istochemically in rat tissues. Anti-OFQ was raised in New Zealand whit e rabbits immunized with a conjugate of synthetic OFQ with bovine seru m albumin. Immunohistochemical analysis was performed by the avidin-bi otin complex method. OFQ immunoreactivity was visualized in the centra l nervous system, anterior pituitary, mucosa of stomach and duodenum, Auerbach's nervous branch and Meissner's nervous branch of the stomach , small intestine and colon: pancreas, adrenal medulla and kidney. Whe n using antiserum pre-incubated with synthetic OFQ, no significant sta in of the cerebrum was detected. These findings suggest that OFQ is wi dely distributed and that the method used is valuable in studying the distribution of OFQ in rats. (C) 1998 Lippincott-Raven Publishers.