DISTRIBUTION OF BETA-1-ADRENOCEPTORS AND BETA-2-ADRENOCEPTORS IN MOUSE TRACHEA AND LUNG - A QUANTITATIVE AUTORADIOGRAPHIC STUDY
DISTRIBUTION OF BETA-1-ADRENOCEPTORS AND BETA-2-ADRENOCEPTORS IN MOUSE TRACHEA AND LUNG - A QUANTITATIVE AUTORADIOGRAPHIC STUDY
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DOI：
10.1111/j.1476-5381.1990.tb14667.x
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发表时间：
1990-01-01
影响因子：
7.3
通讯作者：
GOLDIE, RG
中科院分区：
文献类型：
--
作者：
HENRY, PJ;RIGBY, PJ;GOLDIE, RG
1 Binding and quantitative autoradiography were used to detect [125I]-iodocyanopindolol (I-CYP) associated with .beta.1- and .beta.2-adrenoceptors in mouse tracheal epithelium and airway smooth muscle as well as in lung parenchymal tissue. 2 Specific I-CYP binding to slide-mounted tissue sections of both trachea and parenchyma was of high affinity (KD = 49.0 pM, n = 3 trachea; KD = 118.9 pM, n = 3, parenchyma) and saturable, involving single populations of non-interacting binding sites (Hill coefficient nH = 1.00 .+-. 0.02, trachea; nH = 0.99 .+-. 0.03, parenchyma). 3 Direct measurement of tissue radioactivity also showed that specific I-CYP binding was competitively inhibited in the presence of the .beta.-adrenoceptor antagonists (-)-propranolol (non-selective), CGP 20712A (.beta.1-selective) and ICI 118,551 (.beta.2-selective). Analysis of the competition binding curves for the two selective antagonists revealed mixed populations of .beta.1- and .beta.2-adrenoceptors in the approximate proportions 33% and 67% respectively in mouse trachea and 28% and 72% respectively in mouse lung parenchyma. 4 Densities of autoradiographic grains derived from specific I-CYP binding to alveolar wall tissue and to tracheal epithelium and airway smooth muscle were quantified by a computer-assisted image analysis system, which allowed the contruction of competition binding curves in the presence of the selective .beta.-adrenoceptor antagonists CGP 20712A and ICI 118,551. Analysis of these data demonstrated that in alveolar wall, .beta.1- and .beta.2-adrenoceptor co-existed in the proportions 18% and 82%, respectively. 5 Quantitative autoradiographic analysis also showed that .beta.1- and .beta.2-adrenoceptors were differentially distributed in tracheal epithelium and airway smooth muscle. The .beta.2-adrenoceptor subtype accounted for 71% of all .beta.-adrenoceptors in epithelium. Conversely, .beta.1-adrenoceptors which mediate relaxant responses of mouse trachea to .beta.-adrenoceptor agonists (Henry and Goldie, 1990), accounted for 69% of all .beta.-adrenoceptors in the airway smooth muscle.
