Characteristics and autoradiographic localization of 2-[125I]iodomelatonin binding sites in Djungarian hamster brain.
These studies investigated the characteristics and regional distribution of 2-[125I]iodomelatonin binding in Djungarian hamster brain. The results showed that 2-[125I]iodomelatonin labels two types of binding sites, which resemble the ML-1 and ML-2 melatonin subtypes previously described in other tissues. The 2-[125I]iodomelatonin binding site identified in whole brain membranes has a nanomolar affinity (Kd = 1.48 +/- 0.26 nM) and biochemical and pharmacological characteristics identical to those of the ML-2 site of Syrian hamster whole brain. The 2-[125I]iodomelatonin site in the hypothalamus has a picomolar affinity (Kd = 43.4 +/- 5.1 pM) and resembles the ML-1 site of chicken retina. The localization of 2-[125I]iodomelatonin labeling in autoradiographic studies of the Djungarian hamster brain includes the suprachiasmatic nuclei, the median eminence, the reuniens nucleus, and the paraventricular nucleus of the thalamus.
Duncan
M J
MJ
Department of Pharmacology, Northwestern University Medical School, Chicago, Illinois 60611.
Takahashi
J S
JS
Dubocovich
M L
ML
D000818:Animals; D001345:Autoradiography; D001665:Binding Sites; D001921:Brain / Q000166:cytology / Q000378:metabolism* / Q000648:ultrastructure; D002462:Cell Membrane / Q000276:immunology / Q000378:metabolism / Q000648:ultrastructure; D006224:Cricetinae; D007031:Hypothalamus / Q000166:cytology / Q000378:metabolism / Q000648:ultrastructure; D007457:Iodine Radioisotopes; D008027:Light; D008297:Male; D008550:Melatonin / Q000031:analogs & derivatives* / Q000378:metabolism; D011485:Protein Binding; D011869:Radioligand Assay
D007457:Iodine Radioisotopes; C044556:2-iodomelatonin; D008550:Melatonin