Ideatification and characteristic of Melatonin receptor in human hypothalamus
To vertify whether there exists melatonin 125reeptor (MR) and MRmRNA in human embryonic hypothalamus. Binding assays: ”125Jiodomelatonin binding sites in membrane preparation of human embryonic hypothalamus were studied using radioligand binding assay. Molecular assays: MRmRNA were studied using RT-PCR. Results show saturation studies: the maximum binding capacity (Bmax) was 1.15±4.32 fmol/mg protein and equilibrium dissociation constant (Kd) was 36±8 pmol/L. Kinetic studies: K1=1.3±0.2×107mol·L-1min-1,K1=6.3±A×10-3/min, Kd=48.5±2.1pmol/L. Which is in close agreement with the Kd determined by the saturation studies, Subcellular distribution of specific binding of MR was 0.68, 0.57, 0.31 and 0.07 fmol/mg protein in nucleas, mitochondria, microsme and cytosol respectively. The effect of GTPγ S on specific binding of MR showed that GTPγ S dose-dependently inhibited the binding. Molecular studied showed there exerts MR1a mRNA and MR1b mRNA in human embryonic hypothalamus, but MR1a mRNA is more than MR1b mRNA. The results demonstrated the presence of MR and MRmRNA in human embryonic hypothalamus. GTPγ S inhibits the binding indicating that putative melatonin receptor is coupled to G-proteia. It indicate that hypothalamus is a target organ of melatonin action and direct action of melatonin on the hypothalamus.
radioligand binding assay、membrane preparation
8
R9 ;O4
2005-07-07（万方平台首次上网日期，不代表论文的发表时间）
共1页
93
