Hypothalamic melatonin receptor sites revealed by autoradiography.
125I-Melatonin was used to localize and characterize the melatonin receptor sites in the rat hypothalamus. Autoradiography revealed that displaceable 125I-melatonin binding occurred in suprachiasmatic nuclei and median eminence only. Further studies performed on crude membrane fractions from median eminences revealed high affinity (Kd = 21 pM) melatonin binding sites (Bmax = 8.5 fmol/mg protein). The order of potency of various indole amines to inhibit 125I-melatonin binding was melatonin much greater than N-acetyl-5-hydroxytryptamine greater than 5-methoxytryptamine greater than 5-hydroxytryptamine.
Vanĕcek
J
J
Institute of Physiology, Czechoslovak Academy of Sciences, Prague.
Pavlík
A
A
Illnerová
H
H
D000818:Animals; D001345:Autoradiography; D002462:Cell Membrane / Q000378:metabolism; D007031:Hypothalamus / Q000166:cytology / Q000378:metabolism*; D007457:Iodine Radioisotopes; D007700:Kinetics; D008297:Male; D008473:Median Eminence / Q000378:metabolism; D008550:Melatonin / Q000378:metabolism*; D009928:Organ Specificity; D051381:Rats; D011919:Rats, Inbred Strains; D044094:Receptors, Melatonin; D017981:Receptors, Neurotransmitter / Q000378:metabolism*; D013493:Suprachiasmatic Nucleus / Q000378:metabolism
D007457:Iodine Radioisotopes; D044094:Receptors, Melatonin; D017981:Receptors, Neurotransmitter; D008550:Melatonin