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Autoradiographic localization of β‐adrenoceptor subtypes in guinea‐pig kidney
Author(s) -
Lew R.,
Summers R.J.
Publication year - 1985
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1985.tb08867.x
Subject(s) - pindolol , iodocyanopindolol , adrenergic receptor , beta (programming language) , guinea pig , medulla , propranolol , kidney , endocrinology , medicine , receptor , chemistry , biology , intrinsic activity , agonist , computer science , programming language
1 The distribution of β‐adrenoceptor subtypes in slide‐mounted sections of guinea‐pig kidney has been examined by the technique of in vitro labelling combined with autoradiography. 2 Binding of (‐)‐[ 125 I]‐cyanopindolol (Cyp) to kidney sections equilibrated and dissociated slowly, was saturable and stereoselective with respect to the isomers of propranolol and pindolol. These characteristics were appropriate for binding to β‐adrenoceptors. 3 Delineation of β‐adrenoceptor subtypes was achieved by use of betaxolol (β 1 ‐adrenoceptors) and ICI 118,551 (β 2 ‐adrenoceptors) and computer assisted curve fitting techniques. Both β 1 ‐ and β 2 ‐adrenoceptors were present in the proportions 1:2. 4 3 H‐Ultrofilm images of (‐)‐[ 125 I]‐Cyp binding to guinea‐pig kidney sections showed localized patches of binding in the cortex and concentrated binding in the outer stripe of the medulla. Cortical receptors were of the β 1 subtype and those associated with the outer stripe of the medulla were of the β 2 ‐adrenoceptor subtype. β 1 ‐Adrenoceptors were concentrated over glomeruli and β 2 ‐adrenoceptors over the straight portion of the proximal tubule.