Gulya K, Wamsley J K, Gehlert D, Pelton J T, Duckles S P, Hruby V J, Yamamura H I
J Pharmacol Exp Ther. 1985 Oct;235(1):254-8.
The binding parameters and distribution of somatostatin receptors were determined in the rat brain using in vitro light microscopic autoradiography. The proteolysis resistant somatostatin analog (des-Ala1-, Gly2-desamino-Cys3Tyr11-dicarba3,14-somatostatin; CGP 23,996) radiolabeled with 125iodine proved to be suitable for the localization of somatostatin receptors. Slide mounted tissue sections showed that 125I-CGP 23,996 bound to the somatostatin receptor with a mean Kd value of 4.0 nM. The mean density of receptors (maximum binding) was determined to be 182 fmol/mg of protein. Both somatostatin and unlabeled CGP 23,996 displayed high-affinity binding for somatostatin receptors with IC50 values of 6 and 5 nM, respectively. The areas containing the highest densities of receptors are the basal amygdaloid nucleus, medial habenular nucleus, stratum oriens and radiatum of CA1 and CA2, and the subiculum. High receptor density can also be found in the deep layers of the cingulate cortex and in the deep layers of temporal cortex. Moderate densities occur in the caudate-putamen, the granule cell layer of the cerebellum, CA3 area of the hippocampus, the molecular layer of the dentate gyrus and in the substantia nigra. Brain areas with low specific binding include the molecular layer of the cerebellum and the corpus callosum, a white matter area.
利用体外光学显微镜放射自显影技术，测定了大鼠脑中生长抑素受体的结合参数和分布情况。用125碘标记的抗蛋白水解生长抑素类似物（去丙氨酸1 - 、甘氨酸2 - 去氨基 - 半胱氨酸3 - 酪氨酸11 - 二环杂3,14 - 生长抑素；CGP 23,996）被证明适用于生长抑素受体的定位。载玻片上的组织切片显示，125I - CGP 23,996与生长抑素受体结合，平均解离常数（Kd）值为4.0 nM。受体的平均密度（最大结合量）经测定为182 fmol/mg蛋白质。生长抑素和未标记的CGP 23,996对生长抑素受体均表现出高亲和力结合，其半数抑制浓度（IC50）值分别为6 nM和5 nM。受体密度最高的区域是基底杏仁核、内侧缰核、CA1和CA2的 Oriens层和放射层以及海马下托。在扣带回皮质深层和颞叶皮质深层也可发现高受体密度。中等密度出现在尾状核 - 壳核、小脑颗粒细胞层、海马CA3区、齿状回分子层和黑质。特异性结合较低的脑区包括小脑分子层和胼胝体（一个白质区域）。
