Stankov B, Cozzi B, Lucini V, Capsoni S, Fauteck J, Fumagalli P, Fraschini F
Chair of Chemotherapy, University of Milan, Italy.
Neurosci Lett. 1991 Nov 25;133(1):68-72. doi: 10.1016/0304-3940(91)90059-3.
The distribution and the properties of the melatonin binding sites were characterized in the brain of the rabbit by combined use of autoradiography and in vitro ligand-receptor binding. Autoradiography revealed widespread specific binding in the brain. The pars tuberalis of the pituitary gland, suprachiasmatic nuclei, ventromedial hypothalamic nuclei, tapetum, hippocampus, indusium griseum, cingulate gyrus, cortex and the choroid plexus were intensely labelled. Diffuse specific binding was recorded in the olfactory bulb and the anterior hypothalamus. Series of in vitro ligand-receptor binding experiments, using the anterior hypothalamus, confirmed that the binding was of high affinity and specificity. Coincubation with a non-hydrolyzable GTP analogue provoked a shift in the binding affinity, the numerical values of the Kd increasing from 20-30 pM to 280-300 pM. Apparently the melatonin receptor in the rabbit brain is linked to its second messenger via a G protein, similarly to what has been described for the brain of other vertebrates.
通过放射自显影术和体外配体-受体结合相结合的方法，对家兔脑中褪黑素结合位点的分布和特性进行了表征。放射自显影显示，脑中存在广泛的特异性结合。垂体结节部、视交叉上核、下丘脑腹内侧核、视网膜毯、海马、灰被、扣带回、皮质和脉络丛均有强烈标记。在嗅球和下丘脑前部记录到弥漫性特异性结合。使用下丘脑前部进行的一系列体外配体-受体结合实验证实，这种结合具有高亲和力和特异性。与一种不可水解的GTP类似物共同孵育会引起结合亲和力的变化，解离常数（Kd）的数值从20 - 30 pM增加到280 - 300 pM。显然，家兔脑中的褪黑素受体通过G蛋白与其第二信使相连，这与其他脊椎动物脑内的情况类似。
