Naunyn-Schmiedeberg's Archives of Pharmacology

, Volume 300, Issue 2, pp 101–105 | Cite as

Differentiation of cardiac chronotropic and inotropic effects of β-adrenoceptor agonists

  • Enar Carlsson
  • Carl-Gustaf Dahlöf
  • Anders Hedberg
  • Henry Persson
  • Birgitta Tångstrand
Article

Summary

The relative inotropic and chronotropic activity of β-adrenoceptor agonists was studied in the noradrenaline-depleted, anaesthetized cat. Terbutaline, a selective β2-adrenoceptor agonist, gave at a certain dose a more pronounced chronotropic than inotropic response, while a new β1-selective adrenoceptor agonist (−)-H 80/62 produced the same degree of chronotropic and inotropic stimulation. The results indicate that there is some difference between the β-adrenoceptors in the sinus node mediating chronotropic stimulation and β-adrenoceptors in the ventricular myocardium mediating stimulation of the contractile force. It has been shown that there are both β1- and β2-adrenoceptors in the heart (Carlsson et al., 1972). In the light of this finding it is hypothetized that there are differences in the relative distribution of β1- and β2-adrenoceptors in the sinus node and in the myocardium. Although β1 is the predominant type of β-adrenoceptor in both regions, the β1:β2 concentration ratio seems to be higher in the myo-cardium, than in the sinus node.

Key words

Heart rate Heart contractility β1-Adrenoceptors β2-Adrenoceptors 

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Copyright information

© Springer-Verlag 1977

Authors and Affiliations

  • Enar Carlsson
    • 1
  • Carl-Gustaf Dahlöf
    • 1
  • Anders Hedberg
    • 1
  • Henry Persson
    • 2
  • Birgitta Tångstrand
    • 1
  1. 1.Research LaboratoriesAB HässleMölndalSweden
  2. 2.Research LaboratoriesAB DracoLundSweden

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