Naunyn-Schmiedeberg's Archives of Pharmacology

, Volume 308, Issue 3, pp 191–198 | Cite as

Demonstration of α-adrenoceptors in the rabbit heart by [3H]-dihydroergocryptine binding

  • H. J. Schümann
  • O. -E. Brodde
Article

Summary

For direct identification of α-adrenoceptors in a membrane fraction of the rabbit heart the potent α-adrenoceptor antagonist [3H]-dihydroergocryptine ([3H]-DHE) was used.
  1. 1.

    The binding of [3H]-DHE was saturable with 80 fmol of [3H]-DHE bound/mg protein and of high affinity with an equilibrium dissociation constant (KD) of 11.5 nM. Binding of [3H]-DHE (6 nM) was rapid (t1/2=2 min) and readily reversible. From the ratio of the rate constants for forward (K1=1.97×107 M−1 min−1) and reverse (K2=0.206 min−1) reactions a KD-value of 10 nM was calculated, which is in good agreement with that obtained by equilibrium studies.

     
  2. 2.

    Adrenergic agonists compete for [3H]-DHE binding in an order of potency: (−)adrenaline > (−)phenylephrine≫ (−)isoprenaline and adrenergic antagonists in the order: phentolamine > yohimbine≫ (−)propranolol. Binding is stereospecific as indicated by the greater potency of (−)adrenaline than (±)adrenaline in displacing [3H]-DHE from the binding sites.

     
  3. 3.

    For comparison the binding of the potent β-adrenoceptor antagonist (−)[3H]-dihydroalprenolol ((−)[3H]-DHA) was measured in the same membrane fraction. The number and affinity of β-adrenoceptors amounted to 115 fmol of (−)[3H]-DHA bound/mg protein at saturation and KD=7.9 nM. Adrenergic agonists compete for (−)[3H]-DHA binding in an order of potency: (−)isoprenaline > (−)adrenaline > (−)phenylephrine; and adrenergic antagonists in the order: (−)propranolol≫ phentolamine.

     
  4. 4.

    It is concluded that in a membrane fraction of the rabbit heart there exist binding sites for [3H]-DHE which have characteristics indistinguishable from α-adrenoceptors. Thus the present results are in agreement with previously reported data on the existence of cardiac α-adrenoceptors in the rabbit heart (Schümann et al., 1974; Endoh et al., 1976b).

     

Key words

Cardiac α- and β-adrenoceptors Radioligand binding Rabbit heart [3H]-Dihydroergocryptine (−)[3H]-Dihydroalprenolol 

Abbreviations

[3H]-DHE

[3H]-Dihydroergocryptine

(−)[3H]-DHA

(−)[3H]-dihydroalprenolol

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. Aggerbeck, M., Guellaen, G., Hannoune, J.: Biochemical evidence for the dual action of labetolol on α- and β-adrenoceptors. Br. J. Pharmacol. 62, 543–548 (1978)Google Scholar
  2. Alexander, R. W., Williams, L. T., Lefkowitz, R. J.: Identification of cardiac β-adrenergic receptors by (−)[3H]-alprenolol binding. Proc. Natl. Acad. Sci. USA 72, 1564–1568 (1975)Google Scholar
  3. Brodde, O.-E., Schümann, H. J., Inui, J.: α-Adrenoceptors in the rabbit heart: identification by [3H]-dihydroergocryptine binding. Naunyn-Schmiedeberg's Arch. Pharmacol. 307, R156 (1979)Google Scholar
  4. Ciaraldi, T., Marinetti, G. V.: Thyroxine and propylthiouracil effects in vivo on alpha and beta adrenergic receptors in rat heart. Biochem. Biophys. Res. Commun. 74, 984–991 (1977)Google Scholar
  5. Davis, J. N., Strittmatter, W. Hoyler, E., Lefkowitz, R. J.: [3H]-Dihydroergocryptine binding in rat brain. Brain Res. 132, 327–336 (1977)Google Scholar
  6. Endoh, M., Brodde, O.-E., Schümann, H. J.: Relationship between the level of cAMP and the contractile force under stimulation of α- and β-adrenoceptors by phenylephrine in the isolated rabbit papillary muscle. Naunyn-Schmiedeberg's Arch. Pharmacol. 295, 109–115 (1976a)Google Scholar
  7. Endoh, M., Schümann, H. J.: Frequency-dependence of the positive inotropic effect of methoxamine and naphazoline mediated by α-adrenoceptors in the isolated rabbit papillary muscle. Naunyn-Schmiedeberg's Arch. Pharmacol. 287, 377–389 (1975)Google Scholar
  8. Endoh, M., Schümann, H. J., Krappitz, N., Hillen, B.: α-Adrenoceptors mediating positive inotropic effects on the ventricular myocardium: some aspects of structure-activity relationship of sympathomimetic amines. Jap. J. Pharmacol. 26, 179–190 (1976b)Google Scholar
  9. Endoh, M., Wagner, J., Schümann, H. J.: Influence of temperature on the positive inotropic effect mediated by α- and β-adrenoceptors in the isolated rabbit papillary muscle. Naunyn-Schmiedeberg's Arch. Pharmacol. 287, 61–72 (1975)Google Scholar
  10. Furchgott, R. F.: The classification of adrenoceptors (adrenergic receptors). In: Catecholamines (H. Blaschko and E. Muscholl, (eds), pp. 283–335 Berlin, Heidelberg, New York: Springer 1972)Google Scholar
  11. Govier, W. C.: A positive inotropic effect of phenylephrine mediated through alpha adrenergic receptors. Life Sci. 6, 1361–1365 (1967)Google Scholar
  12. Govier, W. C.: Myocardial alpha adrenergic receptors and their role in the production of a positive inotropic effect by sympathomimetic agents. J. Pharmacol. Exp. Ther. 159, 82–90 (1968)Google Scholar
  13. Guicheney, P., Garay, R. P., Levy-Marchal, C., Meyer, P.: Biochemical evidence for presynaptic and postsynaptic α-adrenoceptors in rat heart membranes: positive homotropic cooperativity of presynaptic binding. Proc. Natl. Acad. Sci. USA 75, 6285–6289 (1978)Google Scholar
  14. Krawietz, W., Poppert, D., Erdmann, E., Glossmann, H., Struck, C.J., Konrad, C.: β-Adrenergic receptors in guinea-pig myocardial tissue. Naunyn-Schmiedeberg's Arch. Pharmacol. 295, 215–224 (1976)Google Scholar
  15. Lefkowitz, R. J.: Identification and regulation of alpha and beta adrenergic receptors. Fed. Proc. 37, 123–129 (1978)Google Scholar
  16. Newmann, K., Williams, L. T., Bishopric, N., Lefkowitz, R. J.: Identification of alpha-adrenergic receptors in human platelets by [3H]-dihydroergocryptine binding. J. Clin. Invest. 61, 395–402 (1978)Google Scholar
  17. Scatchard, G.: The attraction of proteins for small molecules and ions. Ann. N.Y. Acad. Sci. 51, 660–672 (1949)Google Scholar
  18. Schümann, H. J., Endoh, M., Brodde, O.-E.: The time course of the effects of β- and α-adrenoceptor stimulation by isoprenaline and methoxamine on the contractile force and cAMP level of the isolated rabbit papillary muscle. Naunyn-Schmiedeberg's Arch. Pharmacol. 289, 291–302 (1975)Google Scholar
  19. Schümann, H. J., Endoh, M., Wagner, J.: Positive inotropic effects of phenylephrine in isolated rabbit papillary muscle mediated both by α- and β-adrenoceptors. Naunyn-Schmiedeberg's Arch. Pharmacol. 284, 133–148 (1974)Google Scholar
  20. Schümann, H. J., Wagner, J., Knorr, A., Reidemeister, J. Chr., Sadony, V., Schramm, G.: Demonstration in human atrial preparations of α-adrenoceptors mediating positive inotropic effects. Naunyn-Schmiedeberg's Arch. Pharmacol. 302, 333–336 (1978)Google Scholar
  21. Sharma, V. K., Banerjee, S. P.: α-Adrenergic receptors in rat heart: effects of thyroidectomy. J. Biol. Chem. 253, 5277–5279 (1978)Google Scholar
  22. Starke, K.: Alpha sympathomimetic inhibition of adrenergic and cholinergic transmission in the rabbit heart. Naunyn-Schmiedeberg's Arch. Pharmacol. 274, 18–45 (1972)Google Scholar
  23. Starke, K., Borowski, E., Endo, T.: Preferential blockade of presynaptic α-adrenoceptors by yohimbine. Eur. J. Pharmacol. 34, 385–388 (1975)Google Scholar
  24. Tsai, B. S., Lefkowitz, R. J.: [3H]-Dihydroergocryptine binding to alpha adrenergic receptors in canine aortic membranes. J. Pharmacol. Exp. Ther. 204, 606–614 (1978)Google Scholar
  25. Wagner, J., Brodde, O.-E.: On the presence and distribution of α-adrenoceptors in the heart of various mammalian species. Naunyn-Schmiedeberg's Arch. Pharmacol. 302, 239–254 (1978)Google Scholar
  26. Wagner, J., Endoh, M., Reinhardt, D.: Stimulation by phenylephrine of adrenergic alpha- and beta-receptors in the isolated perfused rabbit heart. Naunyn-Schmiedeberg's Arch. Pharmacol. 282, 307–310 (1974)Google Scholar
  27. Wenzel, D. G., Su, J. L.: Interaction between sympathomimetic amines and blocking agents on the rat ventricle strip. Arch. Int. Pharmacodyn. Ther. 160, 379–389 (1966)Google Scholar
  28. Williams, R. S., Lefkowitz, R. J.: Alpha-adrenergic receptors in rat myocardium. Identification by binding of [3H]-dihydroergocryptine. Circ. Res. 43, 721–727 (1978)Google Scholar
  29. Williams, R. S., Lefkowitz, R. J.: Thyroid hormone regulation of alpha-adrenergic receptors: Studies in rat myocardium. J. Cardiovasc. Pharmacol. 1, 181–189 (1979)Google Scholar
  30. Williams, L. T., Lefkowitz, R. J., Watanabe, A. M., Hathaway, D. R., Besch, H. R., Jr.: Thyroid hormone regulation of β-adrenergic receptor number. J. Biol. Chem. 252, 2787–2789 (1977)Google Scholar
  31. Williams, L. T., Mullikin, D., Lefkowitz, R. J.: Identification of α-adrenergic receptors in uterine smooth muscle membranes by [3H]-dihydroergocryptine binding. J. Biol. Chem. 251, 6915–6923 (1976)Google Scholar

Copyright information

© Springer-Verlag 1979

Authors and Affiliations

  • H. J. Schümann
    • 1
  • O. -E. Brodde
    • 1
  1. 1.Pharmakologisches InstitutUniversität EssenEssenFederal Republic of Germany

Personalised recommendations