Pharmacological identity of 2-[125I]iodomelatonin binding sites in chicken brain and sheep pars tuberalis.
2-[125I]Iodomelatonin was used to compare the binding and pharmacological characteristics of the melatonin receptor sites found in chicken brain and sheep pars tuberalis. Scatchard analysis and kinetic experiments showed that 2-[125I]iodomelatonin binds to a single class of site in both tissues with high affinity (Kd 20-34 pM). Competition experiments, using 21 analogues of melatonin, gave inhibition constants (Ki) for the two sites which were significantly correlated (r = 0.985, n = 21, P less than 0.0001). We conclude that the 2-[125I]iodomelatonin binding sites in sheep pars tuberalis and chicken brain have identical binding and pharmacological characteristics.
Sugden
D
D
Physiology Group, Biomedical Sciences Division, King's College, London, U.K.
Chong
N W
NW
D000818:Animals; D001921:Brain / Q000378:metabolism*; D002645:Chickens; D007700:Kinetics; D008550:Melatonin / Q000031:analogs & derivatives* / Q000378:metabolism; D044094:Receptors, Melatonin; D017981:Receptors, Neurotransmitter / Q000378:metabolism*; D012756:Sheep
D044094:Receptors, Melatonin; D017981:Receptors, Neurotransmitter; C044556:2-iodomelatonin; D008550:Melatonin