Speth R C
Department of Veterinary and Comparative Anatomy, Pharmacology and Physiology, Washington State University, Pullman 99164-6520.
Regul Pept. 1993 Mar 19;44(2):189-97. doi: 10.1016/0167-0115(93)90242-z.
The AT2 angiotensin II receptor selective ligand CGP42112 was radioiodinated and used to study AT2 receptor binding sites in the rat brain (combined olfactory bulb, septum, thalamus and midbrain) and whole adrenal. The [125I]CGP 42112 binding was of high affinity, saturable and specific in both tissues. Competition studies with nonselective and angiotensin II receptor subtype selective ligands, and evaluation of the effects of the sulfhydryl reducing agent beta-mercaptoethanol, confirmed that [125I]CGP 42112 bound selectively to the AT2 angiotensin II receptor subtype. [125I]CGP 42112 bound with higher affinity in the brain than in the adrenal. beta-Mercaptoethanol enhanced [125I]CGP 42112 binding in the brain, but did not alter its binding in the adrenal. A similar difference in binding affinity for [125I]sarcosine, isoleucine angiotensin II and enhancement of binding affinity by beta-mercaptoethanol was observed in the rat brain and adrenal. These observations suggest that the AT2 angiotensin II receptor subtypes in the brain and adrenal may differ.
将血管紧张素 II 2 型受体（AT2）选择性配体CGP42112进行放射性碘化，用于研究大鼠脑（嗅球、隔区、丘脑和中脑联合体）和整个肾上腺中的AT2受体结合位点。[125I]CGP 42112在这两种组织中的结合均具有高亲和力、可饱和性且具有特异性。用非选择性和血管紧张素 II 受体亚型选择性配体进行的竞争研究，以及对巯基还原剂β-巯基乙醇作用的评估，证实了[125I]CGP 42112选择性地与血管紧张素 II 2型受体亚型结合。[125I]CGP 42112在脑中的结合亲和力高于肾上腺。β-巯基乙醇增强了[125I]CGP 42112在脑中的结合，但未改变其在肾上腺中的结合。在大鼠脑和肾上腺中观察到对[125I]肌氨酸、异亮氨酸血管紧张素 II 的结合亲和力存在类似差异，且β-巯基乙醇可增强其结合亲和力。这些观察结果表明，脑和肾上腺中的血管紧张素 II 2型受体亚型可能存在差异。
