Vauquelin G, De Backer J P, Ladure P, Flamez A
Department of Molecular and Biochemical Pharmacology, Vrije Universiteit Brussel, Sint-Genesius-Rode, Belgium.
Ann N Y Acad Sci. 1999 Jun 21;881:135-43. doi: 10.1111/j.1749-6632.1999.tb09353.x.
The alpha 2-adrenergic agonist [3H]clonidine and antagonist [3H]idazoxan also label I1 and I2 imidazoline receptors in striatum membranes. They are investigated here in striata from the dog, rat, mouse, rabbit, calf, monkey, and human. I1 receptors were barely detected in the dog, rat, and mouse and only further examined by competition binding experiments in calf, rabbit, and human. I2 receptors were further examined in all species. The centrally acting vasodilators clonidine and rilmenidine were more potent than moxonidine at the I1 receptors. They displayed low potency for the I2 receptors in all species except the rat. In all species examined, the nonsubstituted imidazoline derivatives idazoxan and RX801077 displayed high affinity for the I1 and I2 receptors. Conversely, both stereoisomers of the alkoxy-substituted imidazoline-derivative efaroxan displayed low affinity. The matching binding characteristics of these compounds further stress the structural similarity of the ligand binding sites of I1 and I2 receptors.
α2 - 肾上腺素能激动剂[3H]可乐定和拮抗剂[3H]咪唑克生也标记纹状体膜中的I1和I2咪唑啉受体。本文对来自狗、大鼠、小鼠、兔子、小牛、猴子和人类的纹状体进行了研究。在狗、大鼠和小鼠中几乎检测不到I1受体，仅在小牛、兔子和人类中通过竞争结合实验进一步研究。在所有物种中都对I2受体进行了进一步研究。中枢性血管扩张剂可乐定和利美尼定在I1受体上比莫索尼定更有效。除大鼠外，它们在所有物种的I2受体上效力较低。在所有检测的物种中，未取代的咪唑啉衍生物咪唑克生和RX801077对I1和I2受体具有高亲和力。相反，烷氧基取代的咪唑啉衍生物依酚氯铵的两种立体异构体都表现出低亲和力。这些化合物匹配的结合特性进一步强调了I1和I2受体配体结合位点的结构相似性。
