title: Peptide GEGLSS-like immunoreactivity in the rat central nervous system.
abstract: A rabbit antiserum was raised against the N-terminal fragment peptide, GEGLSS (Gly-Glu-Gly-Leu-Ser-Ser) of bovine neuropeptide AF (NPAF, A18Famide). NPAF is an octadecapeptide isolated from the bovine brain together with neuropeptide FF (NPFF). GEGLSS-like immunoreactivity was localized with immunofluorescence technique in colchicine-treated rats in neuronal cell bodies of the supraoptic (SON) and paraventricular (PVN) hypothalamic nuclei. A few neurons were also observed in the retrochiasmatic part of the SON. GEGLSS-like immunoreactivity was also localized to nerve terminals of the posterior pituitary. No GEGLSS-ir neuronal cell bodies were observed in the medial hypothalamus, in an area that contains NPFF-ir neurons. GEGLSS immunoreactivity was also seen in the fibers and terminals of nucleus of the solitary tract. We injected a retrograde tracer, fluorogold, to the posterior pituitary gland and visualized GEGLSS-ir neuronal cell bodies double-labeled with the tracer in SON, PVN, and SOR. The pituitary stalk transsection totally abolished the GEGLSS-ir structures from the posterior pituitary. Our results suggest that GEGLSS immunoreactivity in the rat brain has a more limited distribution than NPFF immunoreactivity. GEGLSS immunoreactivity was partially colocalized with arginine-vasopressin and oxytocin in neuronal cell bodies in the SON and PVN. Considering the fact that the known rat NPFF-NPAF precursor does not contain GEGLSS structure, the detected GEGLSS immunoreactivity may be derived from a previously unknown precursor.
authors.affiliation: Institute of Biomedicine, Department of Anatomy, University of Helsinki, Finland.
authors.forename: A A
authors.initials: AA
authors.lastname: Aarnisalo
authors.forename: T
authors.initials: T
authors.lastname: Karhunen
authors.forename: S
authors.initials: S
authors.lastname: Vanhatalo
authors.forename: P
authors.initials: P
authors.lastname: Panula
mesh_terms: D000818:Animals; D002417:Cattle; D002490:Central Nervous System / Q000378:metabolism*; D007031:Hypothalamus / Q000378:metabolism; D007150:Immunohistochemistry; D008297:Male; D009292:Narcotic Antagonists / Q000276:immunology; D009479:Neuropeptides / Q000276:immunology*; D009842:Oligopeptides / Q000276:immunology; D010446:Peptide Fragments / Q000494:pharmacology*; D011817:Rabbits; D051381:Rats; D017208:Rats, Wistar
chemical_list: D009292:Narcotic Antagonists; D009479:Neuropeptides; D009842:Oligopeptides; D010446:Peptide Fragments; C109544:glycyl-glutamyl-glycyl-leucyl-seryl-serine; C053651:phenylalanyl-leucyl-phenylalanyl-glutaminyl-prolyl-glutaminyl-arginyl-phenylalaninamide