Heterogeneity of angiotensin II AT2 receptors in the rat brain.
Heterogeneity of angiotensin II AT2 receptors in the rat brain.
复制标题
大鼠脑中血管紧张素 II AT2 受体的异质性。
作者：
K. Tsutsumi;J. Saavedra
血管紧张素II（AT）受体亚型（AT 1，选择性取代的DuP 753，和AT 2，选择性取代的PD 123177和CGP 42112 A）的特点是通过定量放射自显影孵育后，AT激动剂125 I-Sar 1-AT，在特定的脑核的年轻（2周龄）大鼠。与AT 1受体的结合对鸟苷5 '-O-（3-硫代）三磷酸（GTP γ S）存在下的孵育敏感（亲和力降低）。只有室旁核的AT_1受体对百日咳毒素敏感，提示存在AT_1受体亚型的可能性。AT 2受体对GTP γ S的敏感性是异质性的。在腹侧丘脑和内侧膝状体核和蓝斑，AT 2受体的结合是敏感的GTP γ S和百日咳毒素预处理。相反，在下橄榄，结合是不敏感的GTP γ S和百日咳毒素预处理。我们建议命名的AT 2A受体的那些受体敏感的鸟嘌呤核苷酸和百日咳毒素和AT 2B受体的那些显示不敏感的鸟嘌呤核苷酸或百日咳毒素治疗。
Angiotensin II (AT) receptor subtypes (AT1, selectively displaced by DuP 753, and AT2, selectively displaced by PD123177 and CGP42112A) were characterized by quantitative autoradiography after incubation with the AT agonist 125I-Sar1-AT, in specific brain nuclei of young (2-week-old) rats. Binding to AT1 receptors was sensitive (decreased affinity) to incubation in the presence of guanosine 5'-O-(3-thio)triphosphate (GTP gamma S). Only the AT1 receptors in the paraventricular nucleus were sensitive to pertussis toxin, indicating the possibility of the existence of AT1 receptor subtypes. The sensitivity of AT2 receptors to GTP gamma S was heterogeneous. In the ventral thalamic and medial geniculate nuclei and in the locus coeruleus, binding to AT2 receptors was sensitive to GTP gamma S and to pertussis toxin pretreatment. Conversely, in the inferior olive, binding was insensitive to GTP gamma S and to pertussis toxin pretreatment. We propose the nomenclature of AT2A receptors for those receptors sensitive to guanine nucleotides and pertussis toxin and that of AT2B receptors for those showing no sensitivity to guanine nucleotides or pertussis toxin treatment.