title: LPXRFa peptide system in the European sea bass: A molecular and immunohistochemical approach.
abstract: Gonadotropin-inhibitory hormone (GnIH) is a neuropeptide that suppresses reproduction in birds and mammals by inhibiting GnRH and gonadotropin secretion. GnIH orthologs with a C-terminal LPXRFamide (LPXRFa) motif have been identified in teleost fish. Although recent work also suggests its role in fish reproduction, studies are scarce and controversial, and have mainly focused on cyprinids. In this work we cloned a full-length cDNA encoding an LPXRFa precursor in the European sea bass, Dicentrarchus labrax. In contrast to other teleosts, the sea bass LPXRFa precursor contains only two putative RFamide peptides, termed sbLPXRFa1 and sbLPXRFa2. sblpxrfa transcripts were expressed predominantly in the olfactory bulbs/telencephalon, diencephalon, midbrain tegmentum, retina, and gonads. We also developed a specific antiserum against sbLPXRFa2, which revealed sbLPXRFa-immunoreactive (ir) perikarya in the olfactory bulbs-terminal nerve, ventral telencephalon, caudal preoptic area, dorsal mesencephalic tegmentum, and rostral rhombencephalon. These sbLPXRFa-ir cells profusely innervated the preoptic area, hypothalamus, optic tectum, semicircular torus, and caudal midbrain tegmentum, but conspicuous projections also reached the olfactory bulbs, ventral/dorsal telencephalon, habenula, ventral thalamus, pretectum, rostral midbrain tegmentum, posterior tuberculum, reticular formation, and viscerosensory lobe. The retina, pineal, vascular sac, and pituitary were also targets of sbLPXRFa-ir cells. In the pituitary, this innervation was observed close to follicle-stimulating hormone (FSH), luteinizing hormone (LH) and growth hormone (GH) cells. Tract-tracing retrograde labeling suggests that telencephalic and preoptic sbLPXRFa cells might represent the source of pituitary innervation. The immunohistochemical distribution of sbLPXRFa cells and fibers suggest that LPXRFa peptides might be involved in some functions as well as reproduction, such as feeding, growth, and behavior.
authors.affiliation: Department of Biology, Faculty of Environmental and Marine Sciences, University of Cádiz, Marine Campus of International Excellence (CEIMAR) and Agrifood Campus of International Excellence (ceiA3), E-11510 Puerto Real, Spain.|INMAR-CACYTMAR Research Institutes, Puerto Real University Campus, E-11510 Puerto Real, Spain.
authors.forename: José A
authors.initials: JA
authors.lastname: Paullada-Salmerón
authors.affiliation: Department of Biology, Faculty of Environmental and Marine Sciences, University of Cádiz, Marine Campus of International Excellence (CEIMAR) and Agrifood Campus of International Excellence (ceiA3), E-11510 Puerto Real, Spain.|INMAR-CACYTMAR Research Institutes, Puerto Real University Campus, E-11510 Puerto Real, Spain.
authors.forename: Mairi
authors.initials: M
authors.lastname: Cowan
authors.affiliation: Department of Biology, Faculty of Environmental and Marine Sciences, University of Cádiz, Marine Campus of International Excellence (CEIMAR) and Agrifood Campus of International Excellence (ceiA3), E-11510 Puerto Real, Spain.|INMAR-CACYTMAR Research Institutes, Puerto Real University Campus, E-11510 Puerto Real, Spain.
authors.forename: María
authors.initials: M
authors.lastname: Aliaga-Guerrero
authors.affiliation: Institute of Aquaculture of Torre de la Sal, CSIC, Ribera de Cabanes E-12595, Castellón, Spain.
authors.forename: Ana
authors.initials: A
authors.lastname: Gómez
authors.affiliation: Institute of Aquaculture of Torre de la Sal, CSIC, Ribera de Cabanes E-12595, Castellón, Spain.
authors.forename: Silvia
authors.initials: S
authors.lastname: Zanuy
authors.affiliation: Institute of Aquaculture of Torre de la Sal, CSIC, Ribera de Cabanes E-12595, Castellón, Spain.
authors.forename: Evaristo
authors.initials: E
authors.lastname: Mañanos
authors.affiliation: Department of Biology, Faculty of Environmental and Marine Sciences, University of Cádiz, Marine Campus of International Excellence (CEIMAR) and Agrifood Campus of International Excellence (ceiA3), E-11510 Puerto Real, Spain.|INMAR-CACYTMAR Research Institutes, Puerto Real University Campus, E-11510 Puerto Real, Spain.
authors.forename: José A
authors.initials: JA
authors.lastname: Muñoz-Cueto
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000906:Antibodies / Q000378:metabolism; D001492:Bass / Q000033:anatomy & histology / Q000235:genetics / Q000378:metabolism*; D001921:Brain / Q000033:anatomy & histology / Q000378:metabolism; D003001:Cloning, Molecular / Q000379:methods; D005260:Female; D007150:Immunohistochemistry / Q000379:methods; D008297:Male; D008969:Molecular Sequence Data; D036361:Peptide Hormones / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D010802:Phylogeny; D010902:Pituitary Gland / Q000033:anatomy & histology / Q000378:metabolism; D017386:Sequence Homology, Amino Acid
chemical_list: D000906:Antibodies; D036361:Peptide Hormones
keywords: GnIH; LPXRFamide; RRID: AB_2493177; brain; immunohistochemistry; reproduction; sea bass