Tsutsumi K, Strömberg C, Saavedra J M
Section on Pharmacology, National Institute of Mental Health, Bethesda, MD 20892.
Peptides. 1992 Mar-Apr;13(2):291-6. doi: 10.1016/0196-9781(92)90111-f.
Quantitative autoradiography was used to determine the subtype of ANG receptors in the red pulp of the rat spleen. The AT1 antagonist DuP 753 competed for ANG binding with high affinity; binding was abolished by dithiothreitol. The AT2 competitor CGP 42112 A showed lower affinity, and the AT2 competitor PD 123177 did not affect binding at 10(-5) M. These data indicated the presence of only AT1 receptors. AT1 receptor number was similar in immature (2 weeks old) and adult (8 weeks old) rats. Binding was sensitive to guanine nucleotides, suggesting an association with G-proteins. Angiotensin II, at a dose of 10(-7) M, stimulated inositol phosphate formation 33% over control values in spleen from 8-week-old rats. This effect was significantly blocked by 10(-5) M DuP 753. We suggest a possible role of AT1 receptors in the regulation of splenic volume, blood flow, and lymphocyte function.
采用定量放射自显影法测定大鼠脾脏红髓中血管紧张素（ANG）受体的亚型。AT1拮抗剂DuP 753以高亲和力竞争性结合ANG；二硫苏糖醇可消除这种结合。AT2竞争性拮抗剂CGP 42112 A显示出较低的亲和力，而AT2竞争性拮抗剂PD 123177在10^(-5) M浓度时不影响结合。这些数据表明仅存在AT1受体。未成熟（2周龄）和成年（8周龄）大鼠的AT1受体数量相似。结合对鸟嘌呤核苷酸敏感，提示其与G蛋白有关。10^(-7) M剂量的血管紧张素II可使8周龄大鼠脾脏中的肌醇磷酸生成量比对照值增加33%。10^(-5) M DuP 753可显著阻断此效应。我们认为AT1受体可能在脾脏体积、血流量和淋巴细胞功能的调节中发挥作用。
