Melatonin binding sites in senegal sole: day/night changes in density and location in different regions of the brain.
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.
Oliveira
Catarina
C
Faculty of Biology, Department of Physiology, Murcia University, Murcia, Spain.
Lopez-Olmeda
José Fernando
JF
Delgado
María Jesus
MJ
Alonso-Gómez
Angel Luis
AL
Sánchez-Vázquez
Francisco Javier
FJ
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
D008550:Melatonin