Healy D P, Münzel P A, Insel P A
Circ Res. 1985 Aug;57(2):278-84. doi: 10.1161/01.res.57.2.278.
beta-Adrenergic receptor subtypes were localized and differentiated in rat kidney slices by in vitro autoradiography using the nonselective beta-antagonist [125I]iodocyanopindolol in the presence of the selective agents betaxolol (beta 1) and zinterol (beta 2). [125I]Iodocyanopindolol binding to kidney sections in the presence of these agents could be differentiated into high- and low-affinity components as predicted by the subtype selectivity of the compounds. Autoradiography revealed that: beta-adrenergic receptors were highly concentrated within the renal cortex, especially in glomeruli and juxtaglomerular granule cells, and to tubular sites in the cortex and medulla; [125I]iodocyanopindolol labeling of the juxtaglomeruluar granule cells was abolished at lower concentrations (10(-8) M) of betaxolol than was the labeling of glomeruli (10(-6)--10(-4) M); and zinterol had little effect on labeling of juxtaglomerular granule cells and glomeruli unless high concentrations were used, whereas the tubular labeling in medulla was much more sensitive to incubation with zinterol. These results indicate that beta 1- and beta 2-adrenergic receptor subtypes are differentially distributed within the kidney: beta 1, predominantly contained in juxtaglomerular granule cells and glomeruli, and beta 2, predominantly in medullary tubules. In vitro autoradiography provides a useful means to examine different receptor populations in discrete tissue areas.
在选择性药物倍他洛尔（β1）和丁萘氧丙醇（β2）存在的情况下，使用非选择性β拮抗剂[125I]碘氰吲哚洛尔，通过体外放射自显影法对大鼠肾切片中的β肾上腺素能受体亚型进行定位和区分。在这些药物存在的情况下，[125I]碘氰吲哚洛尔与肾切片的结合可如化合物的亚型选择性所预测的那样，区分为高亲和力和低亲和力成分。放射自显影显示：β肾上腺素能受体高度集中在肾皮质内，尤其是在肾小球和近球颗粒细胞中，以及皮质和髓质的肾小管部位；与肾小球标记（10(-6)-10(-4)M）相比，较低浓度（10(-8)M）的倍他洛尔即可消除近球颗粒细胞的[125I]碘氰吲哚洛尔标记；除非使用高浓度，丁萘氧丙醇对近球颗粒细胞和肾小球的标记影响很小，而髓质中的肾小管标记对丁萘氧丙醇孵育更为敏感。这些结果表明，β1和β2肾上腺素能受体亚型在肾内分布不同：β1主要存在于近球颗粒细胞和肾小球中，β2主要存在于髓质肾小管中。体外放射自显影为检查离散组织区域中的不同受体群体提供了一种有用的方法。
