Melatonin receptors in chick brain: characterization and localization.
Melatonin receptors in chick brain: characterization and localization.
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DOI：
10.1210/endo-125-1-363
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发表时间：
1989-07
期刊：
影响因子：
4.8
通讯作者：
S. Rivkees;Vincent M. Cassone;D. Weaver;S. Reppert
中科院分区：
文献类型：
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作者：
S. Rivkees;Vincent M. Cassone;D. Weaver;S. Reppert
以具有生物活性的褪黑素类似物[~(125)I]褪黑素[~(125)I]Mel为标记物，用放射自显影和放射自显影对雏鸡脑内的褪黑素受体进行了定位。在全脑的膜上，放射受体研究表明[125I]MEL是一个高亲和力的结合部位，其平衡解离常数为47.2+/-11.5(均值+/-扫描电子显微镜)PM，密度为37.8+/-8.5fmol/mg蛋白。褪黑素和与之密切相关的褪黑素类似物的结合是可逆和竞争性抑制的，但不是去甲肾上腺素或5-羟色胺。体外脑放射自显影研究显示褪黑素受体广泛分布。在视觉系统的视网膜突起核和整合核，包括哺乳动物视交叉上核的鸟类同系物中，观察到特异性的I-MEL结合。与唤醒和发声相关的听觉中继核和边缘结构也被特别标记。褪黑素受体在雏鸡大脑中的广泛分布与褪黑素受体在哺乳动物大脑中的分布非常有限形成鲜明对比，这表明鸟类的感觉系统受到褪黑素的影响。
Melatonin receptors in chick brain were characterized by RRA and localized by in vitro autoradiography, using [125I]melatonin [( 125I]MEL), a biologically active melatonin analog. In membranes from whole brain, radioreceptor studies revealed a high affinity [125I]MEL binding site with an equilibrium dissociation constant of 47.2 +/- 11.5 (mean +/- SEM) pM and a density of 37.8 +/- 8.5 fmol/mg protein. Binding was reversible and competitively inhibited by melatonin and closely related melatonin analogs, but not be norepinephrine or serotonin. In vitro autoradiographic studies of brain revealed a widespread distribution of melatonin receptors. Specific I-MEL binding was observed in retinorecipient and integrative nuclei of the visual system including the avian homolog of the mammalian suprachiasmatic nuclei. Auditory relay nuclei and limbic structures associated with arousal and vocalization were also specifically labeled. This widespread distribution of putative melatonin receptors in chick brain is in marked contrast to the very restricted distribution of melatonin receptors in mammalian brain and suggests that avian sensory systems are affected by melatonin.