Naunyn-Schmiedeberg's Archives of Pharmacology

, Volume 331, Issue 1, pp 40–51 | Cite as

Direct labelling of β2-adrenoceptors

Comparison of binding potency of 3H-ICI 118,551 and blocking potency of ICI 118,551
  • Horst Lemoine
  • Bernhard Ehle
  • Alberto J. Kaumann


A radioligand that selectively labels β2-adrenoceptors, 3H-ICI 118,551 (3H-ICI), is introduced. Experiments were performed on guinea-pig tissues. The binding characteristics of 3H-ICI on lung membrane particles are compared with the blocking characteristics of ICI 118,551 against the tracheo-relaxant effects of (−)-noradrenaline, (−)-adrenaline and (±)-fenoterol. Binding to both β1- and β2-adrenoceptors were also performed with 3H-(−)-bupranolol on lung and ventricular myocardium. The binding inhibition characteristics of unlabelled ICI 118,551 on ventricle were compared with its characteristics as antagonist of the positive chronotropic effects of (−)-noradrenaline, (−)-adrenaline and (±)-fenoterol in spontaneously beating right atria.

  1. 1.

    ICI 118,551 blocked more the relaxant effects of (±)-fenoterol and (−)-adrenaline than those of (−)-noradrenaline on trachea. The positive chronotropic effects of (±)-fenoterol on sinoatrial node were blocked more than those of both (−)-adrenaline and (−)-noradrenaline. A non-linear regression analysis of blocking data with ICI 118,551 according to the model of Lemoine and Kaumann (1983) revelas that both β1- and β2-adrenoceptors contribute to the tracheo-relaxant and positive chronotropic effects of agonists. The estimated equilibrium dissociation constants pKB (-log KB=pKB; mol/l) were 7.1 and 9.6 for β1- and β2-adrenoceptors, respectively. Tracheal β2-adrenoceptors contribute 99%, 97% and 7%, sinoatrial β2-adrenoceptors contribute 76%, 3% and 0% to the fractional stimuli induced by (±)-fenoterol, (−)-adrenaline and (−)-noradrenaline, respectively.

  2. 2.

    3H-ICI associated to β2-adrenoceptors of lung membranes with a kon of 0.52 l·nmol−1·min−1 and dissociated with a koff of 0.19 min−1. 3H-ICI bound to lung β2-adrenoceptors with an equilibrium dissociation constant pKL* of 9.2. Unlabelled ICI 118,551, (−)-bupranolol, (+)-bupranolol, (−)-adrenaline, (−)-noradrenaline and (±)-fenoterol competed with 3H-ICI for lung β2-adrenoceptors with pKL-values of 9.0, 9.4, 8.1, 5.9, 4.9 and 6.4, respectively.

  3. 3.

    3H-(−)-bupranolol associated to β-adrenoceptors of lung membranes with a kon 1.2 l·nmol−1·min−1 and dissociated with a koff of 0.26 min−1. 3H-(−)-bupranolol bound to lung β2-adrenoceptors and to heart β1-adrenoceptors with a pKL of 9.6 and a pKL of 8.8, respectively. Lung β2- and β1-adrenoceptors comprised 3/4 and 1/4 of the β-adrenoceptor population, as estimated independently with 3H-ICI and 3H-(−)-bupranolol; 1/5 of ventricular β-adrenoceptors was β2, 4/5 β1.

  4. 4.

    The binding characteristics including stereoselectivity show that 3H-(−)-ICI 118,551 is useful to label nearly exclusively β2-adrenoceptors in a system containing both β1- and β2-adrenoceptors. The affinity for β2-adrenoceptors of competing ligands can be determined straightforwardly without interference of β1-adrenoceptors. The low affinity for lung β2-adrenoceptors but high tracheorelaxant potency of agonists suggest the existence of a large β1-adrenoceptor reserve.


Key words

Lung and heart β1- and β2-adrenoceptors 3H-ICI 118,551 and 3H-(−)-bupranolol (−)-Adrenaline and (−)-noradrenaline Binding and blockade 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Bilski AJ, Halliday SE, Fitzgerald JD, Wale JL (1983) The pharmacology of a β 2-selective adrenoceptor antagonist (ICI 118,551). J Cardiovasc Pharmacol 5:430–437Google Scholar
  2. Blinks JR (1965) Convenient apparatus for recording contractions of isolated muscle. J Appl Physiol 20:755–757Google Scholar
  3. Brodde O-E, Kuhlhoff F, Arroyo J, Pyrwarra A (1983) No evidence for temperature-dependent changes in the pharmacological specificity of β 1- and β 2-adrenoceptors in rabbit lung membranes. Naunyn-Schmiedeberg's Arch Pharmacol 322:20–28Google Scholar
  4. Carlsson E, Åblad B, Brandström A, Carlsson B (1972) Differentiated blockade of the chronotropic effects of various adrenergic stimuli in the cat heart. Life Sci 11:953–958Google Scholar
  5. Ehle B, Lemoine H, Kaumann AJ (1985) Improved evaluation of binding of ligands to membranes containing several receptor subtypes. Naunyn-Schmiedeberg's Arch Pharmacol 331:52–59Google Scholar
  6. Engel G, Hoyer D, Berthold R, Wagner H (1981) (±)-125Iodocyanpindolol, a new ligand for β-adrenoceptors: identification and quantitation of subclasses of β-adrenoceptors in guinea pig. Naunyn-Schmiedeberg's Arch Pharmacol 317:277–285Google Scholar
  7. Furchgott RF (1976) Postsynaptic adrenergic receptor mechanisms in vascular smooth muscle. In: Bevan JA (ed) Vascular neuroeffector mechanisms, 2nd Int Symp Odense. Karger, Basel, pp 131–142Google Scholar
  8. Johansson L-H, Persson H (1983) β 2-Adrenoceptors in guinea-pig atria. J Pharm Pharmacol 35:804–807Google Scholar
  9. Kaumann AJ, Birnbaumer L (1974) Characteristics of the adrenergic receptor coupled to myocardial adenylyl cyclase. Stereo-specificity for ligands and determinations of apparent affinity constants for β-blockers. J Biol Chem 249:7874–7885Google Scholar
  10. Kaumann AJ, Birnbaumer L, Wittmann R (1978) Heart β-adrenoceptors. In: O'Malley BW, Birnbaumer L (eds) Hormone receptors, vol 3. Academic Press, New York, pp 133–177Google Scholar
  11. Kaumann AJ, Marano M (1982) On equilibrium constants for complexes of drug-receptor subtypes. Selective and non-selective interactions of partial agonists with two plausible β-adrenoceptor subtypes mediating positive chronotropic effects of (−)-isoprenaline in kitten atria. Naunyn-Schmiedeberg's Arch Pharmacol 318:192–201Google Scholar
  12. Kaumann AJ, Lemoine H (1983) Separation of catecholamine binding and relaxation in bovine tracheal muscle dependent upon cyclic AMP. J Physiol 348:47PGoogle Scholar
  13. Kaumann AJ, Lemoine H (1985) Direct labelling of myocardial β 1-adrenoceptors. Comparison of binding affinity of 3H-(−)-bisoprolol with its blocking potency. Naunyn-Schmiedeberg's Arch Pharmacol 331:27–39Google Scholar
  14. Lemoine H, Kaumann AJ (1982) A novel analysis of concentration-dependence of partial agonism. Ring-demethylation of bupranolol results in a high affinity partial agonist (K 105) for myocardial and tracheal β-adrenoceptors. Naunyn-Schmiedeberg's Arch Pharmacol 320:130–144Google Scholar
  15. Lemoine H, Kaumann AJ (1983) A model for the interaction of competitive antagonists with two receptor-subtypes characterized by a Schild-plot with apparent slope unique. Agonist-dependent enantiomeric affinity ratios for bupranolol in tracheae but not in right atria of guinea pigs. Naunyn-Schmiedeberg's Arch Pharmacol 322:111–120Google Scholar
  16. Lowry OH, Rosebrough NJ, Farr AL, Randall RJ (1951) Protein measurement with the Folin phenol reagent. J Biol Chem 193:265–275Google Scholar
  17. Minneman KP, Puckett AM, Jensen AD, Rinard GA (1983) Regional variation in beta adrenergic receptors in dog trachea: correlation of receptor density and in vitro relaxation. J Pharmacol Exp Ther 226:140–146Google Scholar
  18. Morris TH, Sandrock K, Kaumann AJ (1981) 3H-(−)-Bupranolol, a new β-adrenoceptor radioligand: characterization of its binding to kitten heart β-adrenoceptors. Naunyn-Schmiedeberg's Arch Pharmacol 317:19–25Google Scholar
  19. Motulsky HJ, Mahan LC (1984) The kinetics of competitive radioligand binding predicted by the law of mass action. Mol Pharmacol 25:1–9Google Scholar
  20. O'Donnell SR, Wanstall JC (1979a) The importance of choice of agonist in studies designed to predict β 2:β 1 adrenoceptor selectivity of antagonists from pA2 values on guinea-pig trachea and atria. Naunyn-Schmiedeberg's Arch Pharmacol 308:183–190Google Scholar
  21. O'Donnell SR, Wanstall JC (1979b) pA2 values of selective β-adrenoceptor antagonists on isolated atria demonstrate a species difference in the β-adrenoceptor populations mediating chronotropic responses in cat and guinea pig. J Pharm Pharmacol 31:686–690Google Scholar
  22. O'Donnell SR, Wanstall JC (1980) Evidence that ICI 118,551 is a potent, highly beta2-selective adrenoceptor antagonist and can be used to characterize beta-adrenoceptor populations in tissues. Life Sci 27:671–677Google Scholar
  23. O'Donnell SR, Wanstall JC (1981) Pharmacological approaches to the characterization of β-adrenoceptor populations in tissues. J Auton Pharma 1:305–312Google Scholar
  24. Scatchard G (1949) The attractions of proteins for small molecules and ions. Ann NY Acad Sci 51, 660–672Google Scholar
  25. Stephenson RP (1956) A modification of receptor theory. Br J Pharmacol 11:379–393Google Scholar
  26. Trendelenburg U (1968) The effect of cocaine on the pacemaker of isolated guinea-pig atria. J Pharmacol Exp Ther 161:222–231Google Scholar
  27. Wallukat G, Wollenberger A (1984) Mechanism of sensitization to isoprenaline (ISO) in cultured rat heart cells exposed to pyruvate of (+)-lactate. Abstract of the Meeting of the East European Section of the International Society of Heart Research, Szeged, Hungary, AugustGoogle Scholar
  28. Walter M, Lemoine H, Kaumann AJ (1984) Stimulation and blocking effects of optical isomers of pindolol on the sinoatrial node and trachea of guinea pig. Role of β-adrenoceptor subtypes in the dissociation between blockade and stimulation. Naunyn-Schmiedeberg's Arch Pharmacol 327:159–175Google Scholar
  29. Wollenberger A, Wallukat G (1982) Sensitization by lactate and pyruvate of rocker-cultured rat myocardial cells to isoproterenol. In: Calderra CM, Harris P (eds) Advances in studies on heart metabolism. CLUEB, Bologna, pp 133–137Google Scholar

Copyright information

© Springer-Verlag 1985

Authors and Affiliations

  • Horst Lemoine
    • 1
  • Bernhard Ehle
    • 2
  • Alberto J. Kaumann
    • 1
  1. 1.Klinische Physiologie, Physiologisches Institut der Universität DüsseldorfDüsseldorfFederal Republic of Germany
  2. 2.Medizinische Statistik und Biomathematik der Universität DüsseldorfDüsseldorfFederal Republic of Germany

Personalised recommendations