Dam T V, Escher E, Quirion R
Douglas Hospital Research Centre, McGill University, Verdun, Qué., Canada.
Brain Res. 1990 Jan 1;506(1):175-9. doi: 10.1016/0006-8993(90)91218-6.
The autoradiographic distribution of the neurokinin (NK)-3 receptor sub-type was visualized in the rat brain using [3H]senktide, a highly selective ligand, [3H]Senktide apparently binds to a single class of high affinity (Kd = 2.8 +/- 1.0 nM), low capacity (Bmax = 31.2 +/- 3.0 fmol/mg protein) sites in rat brain cortex. The ligand selectivity pattern reveals that eledoisin and senktide are potent competitors of both [3H]senktide and [125I]Bolton-Hunter eledoisin binding sites demonstrating the NK-3 nature of these sites. Autoradiographic data show that [3H]senktide binding sites are concentrated in mid-cortical layers, supraoptic nucleus, zona incerta, basolateral nucleus of the amygdala and interpeduncular nucleus. Much lower densities of binding are seen in most other areas such as the caudate-putamen and cerebellum. This distribution is similar, but not identical, to that previously reported for NK-3 sites using less selective ligands. It is most likely because less selective probes also bind to other classes of NK receptors. The higher selectivity of [3H]senktide is thus an important advantage for the precise characterization of NK-3 receptor binding parameters.
利用高选择性配体[3H]senktide在大鼠脑中观察到神经激肽（NK）-3受体亚型的放射自显影分布。[3H]Senktide显然与大鼠脑皮质中一类单一的高亲和力（Kd = 2.8 +/- 1.0 nM）、低容量（Bmax = 31.2 +/- 3.0 fmol/mg蛋白质）位点结合。配体选择性模式表明，eledoisin和senktide是[3H]senktide和[125I]Bolton-Hunter eledoisin结合位点的有效竞争者，证明了这些位点的NK-3性质。放射自显影数据显示，[3H]senktide结合位点集中在皮质中层、视上核、未定带、杏仁核基底外侧核和脚间核。在大多数其他区域，如尾状核-壳核和小脑中，结合密度要低得多。这种分布与先前使用选择性较低的配体报道的NK-3位点分布相似，但不完全相同。这很可能是因为选择性较低的探针也与其他类别的NK受体结合。因此，[3H]senktide的较高选择性是精确表征NK-3受体结合参数的一个重要优势。
