Localization and quantification of melatonin receptors in the diencephalon and posterior telencephalon of the sheep brain
Localization and quantification of melatonin receptors in the diencephalon and posterior telencephalon of the sheep brain
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DOI：
10.1111/j.1600-079x.1998.tb00365.x
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发表时间：
1998-01-01
影响因子：
10.3
通讯作者：
Pelletier, J
中科院分区：
文献类型：
--
作者：
Chabot, V;Caldani, M;Pelletier, J
为了更好地了解褪黑激素控制神经内分泌活动的机制，我们试图准确定义绵羊褪黑激素受体密度最高的大脑区域，并确定其特征。I-125-褪黑激素的特异性标记首先通过三只母羊后端脑和间脑脑切片的放射自显影术揭示。然后通过图像分析准确确定结合最高的五个结构（即，斜束核的垂直部和水平部、间隔区、终纹床核和下丘脑腹内侧区）的范围和位置。与图像分析给出的地标相比，另一只母羊的冠状切片照片可以准确定义第二步要打孔的结构的极限。在六只母羊中，先前确定的五种结构中的每一种都是从冷冻冠状切片中冲压出来的，并通过斯卡查德分析单独研究了 I-125-褪黑激素与膜制剂的结合。 B/F比和结合(B)之间的相关系数在0.96-0.98范围内，表明可以对这些不同结构进行精确定量。 Bmax 在终纹床核、间隔区和下丘脑腹内侧区最高（分别为 1.38、1.25 和 0.95 fmol/mg 蛋白质）。所有 Kd 值均小于 10 pM，希尔系数接近 1，表明存在单一类别的 I-125-褪黑激素受体。这些结果表明用于准确测量大脑结构中低浓度褪黑激素受体的方法的可靠性。此外，下丘脑腹内侧区域被发现富含褪黑激素受体，已知该区域参与绵羊的中枢促性腺激素控制。
In an attempt to better understand the mechanisms by which melatonin controls neuroendocrine activity, we tried to define with accuracy the brain areas where the density of melatonin receptors is the highest in sheep and to establish their characteristics, The specific labelling of I-125-melatonin was first revealed by autoradiography on brain sections of the posterior telencephalon and diencephalon in three ewes. The extent and position of the five structures where the binding was found to be the highest (i.e., the pars verticalis and pars horizontalis of the nucleus tractus diagonalis, the septal area, the bed nucleus of the stria terminalis, and the ventromedial hypothalamic area) were then accurately defined by image analysis. In comparison to the landmarks given by image analysis, photographs of coronal sections of another ewe permitted the accurate definition elf the limits of The structures to be punched in a second step. In six ewes, each of the five structures previously identified were punched from frozen coronal sections and binding of I-125-melatonin to membrane preparations was studied individually by Scatchard analysis. The correlation coefficient between the B/F ratio and binding (B) was in the range of 0.96-0.98, indicating that a precise quantification was possible in these different structures. The Bmax was the highest in the bed nucleus of the stria terminalis, the septal area, and the ventromedial hypothalamic area (1.38, 1.25, and 0.95 fmol/mg protein, respectively). All Kd values were less than 10 pM and the Hill coefficient was close to 1, indicating the presence of a single class of receptor to I-125-melatonin. These results indicate the reliability of a method used to measure with accuracy low concentrations of melatonin receptors in brain structures. In addition, the ventromedial hypothalamic area was found to be rich in melatonin receptors, This region is known to be involved in the central gonadotrope control in sheep.