2-[125I]iodomelatonin binding sites in the bovine hippocampus are not sensitive to guanine nucleotides
Articolo
Data di Pubblicazione:
1995
Citazione:
2-[125I]iodomelatonin binding sites in the bovine hippocampus are not sensitive to guanine nucleotides / R. Nonno, V. Lucini, B. Stankov, F. Fraschini. - In: NEUROSCIENCE LETTERS. - ISSN 0304-3940. - 194:1-2(1995 Jul 14), pp. 113-116.
Abstract:
The discrete distribution and pharmacological characteristics of melatonin binding sites in the bovine hippocampus were determined. Autoradiography revealed the presence of melatonin binding sites in the stratum lacunosum-molecularis of the hippocampus (CA1), stratum molecularis of the subiculum and in the enthorhinal cortex. Analysis of the kinetic parameters demonstrated that the binding was stable and reversible, represented by a single class high affinity binding sites (Kd 40 pM, Bmax = 3.9 fmol/mg protein). However, 2-iodomelatonin and 2-bromomelatonin inhibited 2-[125I]iodomelatonin binding in a biphasic manner. The presence of 4 mM CaCl2 did not cause changes in the affinity constant values. Finally, experiments performed with GTP gamma S revealed that binding affinity was not decreased even with high concentrations of the nucleotide. These findings show that 2-[125I]iodomelatonin binding sites in the bovine parahippocampal-hippocampal region possess some binding features not common to melatonin receptors described so far; moreover they seem not to be linked to a regulatory G-protein.
Tipologia IRIS:
01 - Articolo su periodico
Keywords:
Animals; Cattle; Guanine Nucleotides; Hippocampus; Dose-Response Relationship, Drug; Kinetics; Melatonin; Autoradiography; Male; Female; Binding Sites
Elenco autori:
R. Nonno, V. Lucini, B. Stankov, F. Fraschini
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