title: Melatonin binding sites in senegal sole: day/night changes in density and location in different regions of the brain.
abstract: We localized melatonin binding sites in different brain regions (optic tectum, telencephalon, cerebellum, hypothalamus, olfactory bulbs, and medulla oblongata) of Senegal sole, a species of aquaculture interest, and checked day/night changes in density (B(max)) at mid-light (ZT06) and mid-dark (ZT18). Plasma melatonin was measured using a radioimmunoassay, while binding assays were performed using 2-[(125)I]iodomelatonin as a radioligand. Plasma melatonin concentrations were significantly lower at mid-light (189.5+/-46 pg/ml) than mid-dark (455.5+/-163 pg/ml). Values of B(max) were statistically significantly higher in the optic tectum (5.6+/-0.6 and 12.3+/-1 fmol/mg prot, at mid-light and mid-dark, respectively) and in the cerebellum (7.7+/-1.1 and 10.6+/-1.3 fmol/mg prot, at mid-light and mid-dark, respectively). Significant day/night differences were only observed in these two tissues. These results show for the first time the distribution of melatonin binding sites within the brain of a flatfish species and their lack of down-regulation.
authors.affiliation: Faculty of Biology, Department of Physiology, Murcia University, Murcia, Spain.
authors.forename: Catarina
authors.initials: C
authors.lastname: Oliveira
authors.forename: José Fernando
authors.initials: JF
authors.lastname: Lopez-Olmeda
authors.forename: María Jesus
authors.initials: MJ
authors.lastname: Delgado
authors.forename: Angel Luis
authors.initials: AL
authors.lastname: Alonso-Gómez
authors.forename: Francisco Javier
authors.initials: FJ
authors.lastname: Sánchez-Vázquez
mesh_terms: D000818:Animals; D001522:Behavior, Animal; D001665:Binding Sites; D001921:Brain / Q000378:metabolism*; D002940:Circadian Rhythm; D015536:Down-Regulation; D005247:Feeding Behavior; D005399:Fishes; D005786:Gene Expression Regulation; D008027:Light; D008124:Locomotion; D008550:Melatonin / Q000097:blood / Q000737:chemistry*; D008953:Models, Anatomic; D010870:Pineal Gland / Q000378:metabolism
chemical_list: D008550:Melatonin