Biomaterial Database

The ontogeny of 2-[125I]iodomelatonin binding sites in chicken brain. 1992

N W Chong, and D Sugden

Physiology Group, Biomedical Sciences Division, King's College, London, UK.

The characteristics of the binding sites for 2-[125I]iodomelatonin were studied in chicken brain membranes during development. Specific binding, defined using cold melatonin (1 microM), was detected as early as 8-day-old embryos. Scatchard analysis of saturation experiments showed that 2-[125I]iodomelatonin binds to a single class of site at all ages tested (8-day-old embryos to 3-month-old chicks). Binding affinity (Kd) did not change during development (18-31 pM), but the maximal number of binding sites (Bmax) increased until embryonic day 18, and then remained relatively constant until 30 days of age. A further increase in Bmax was seen at 3 months of age. Guanosine 5'-triphosphate (GTP, 1 mM) inhibited 2-[125I]iodomelatonin binding at all ages suggesting that the melatonin binding site is coupled to a guanine nucleotide binding protein at a very early stage of development. Competition experiments with a number of melatonin analogues indicated that the binding site detected in the brain at embryonic day 8 was pharmacologically identical to that observed 15 days after hatching.

UI	MeSH Term	Description	Entries
D007457	Iodine Radioisotopes	Unstable isotopes of iodine that decay or disintegrate emitting radiation. I atoms with atomic weights 117-139, except I 127, are radioactive iodine isotopes.	Radioisotopes, Iodine
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008550	Melatonin	A biogenic amine that is found in animals and plants. In mammals, melatonin is produced by the PINEAL GLAND. Its secretion increases in darkness and decreases during exposure to light. Melatonin is implicated in the regulation of SLEEP, mood, and REPRODUCTION. Melatonin is also an effective antioxidant.
D009928	Organ Specificity	Characteristic restricted to a particular organ of the body, such as a cell type, metabolic response or expression of a particular protein or antigen.	Tissue Specificity,Organ Specificities,Specificities, Organ,Specificities, Tissue,Specificity, Organ,Specificity, Tissue,Tissue Specificities
D001921	Brain	The part of CENTRAL NERVOUS SYSTEM that is contained within the skull (CRANIUM). Arising from the NEURAL TUBE, the embryonic brain is comprised of three major parts including PROSENCEPHALON (the forebrain); MESENCEPHALON (the midbrain); and RHOMBENCEPHALON (the hindbrain). The developed brain consists of CEREBRUM; CEREBELLUM; and other structures in the BRAIN STEM.	Encephalon
D002642	Chick Embryo	The developmental entity of a fertilized chicken egg (ZYGOTE). The developmental process begins about 24 h before the egg is laid at the BLASTODISC, a small whitish spot on the surface of the EGG YOLK. After 21 days of incubation, the embryo is fully developed before hatching.	Embryo, Chick,Chick Embryos,Embryos, Chick
D002645	Chickens	Common name for the species Gallus gallus, the domestic fowl, in the family Phasianidae, order GALLIFORMES. It is descended from the red jungle fowl of SOUTHEAST ASIA.	Gallus gallus,Gallus domesticus,Gallus gallus domesticus,Chicken
D000375	Aging	The gradual irreversible changes in structure and function of an organism that occur as a result of the passage of time.	Senescence,Aging, Biological,Biological Aging
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D001665	Binding Sites	The parts of a macromolecule that directly participate in its specific combination with another molecule.	Combining Site,Binding Site,Combining Sites,Site, Binding,Site, Combining,Sites, Binding,Sites, Combining