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Research in Experimental Medicine

, Volume 166, Issue 2, pp 165–171 | Cite as

Stimulation by phenylephrine of myocardial alpha-adrenoceptors in the left ventricle of the cat

  • E. Rodrigues-Pereira
  • J. Wagner
Article

Summary

In the anesthetized cat phenylephrine in doses of 10−8, 3 × 10−8 and 10−7 moles/kg caused an increase of dp/dtmax. of the left ventricle without altering the heart rate. This cardiostimulating effect was inhibited by the α-adrenolytic drug phentolamine (10−6 moles/kg). The ß-adrenolytic agent prindolol (10−7 moles/kg), which inhibited the increase of dp/dtmax evoked by isoprenaline as well as by noradrenaline did not influence the positive inotropic effect of phenylephrine, thus favouring the view that there exist myocardial α-adrenoceptors in the ventricle of the cat.

Key words

Phenylephrine phentolamine prindolol dp/dtmax 

Zusammenfassung

An der narkotisierten Katze verursacht Phenylephrin in Dosen von 10−8, 3 × 10−8 und 10−7 Mol/kg einen Anstieg von dp/dtmax des linken Ventrikels, ohne dabei die Schlagfrequenz zu ändern. Die kardiostimulierende Wirkung des Phenylephrins wurde durch das α-Adrenolytikum Phentolamin (10−6 Mol/kg) gehemmt. Das ß-Adrenolytikum Prindolol (10−7 Mol/kg), das den durch Isoprenalin und Noradrenalin verursachten Anstieg von dp/dtmax hemmte, war ohne Wirkung gegenüber der positiv inotropen Wirkung des Phenylephrins. Diese Untersuchungen stützen die Auffassung, daß im Ventrikel der Katze myokardiale α-Adrenozeptoren vorkommen.

Schlüsselwörter

Phenylephrin Phentolamin Prindolol dp/dtmax 

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Copyright information

© Springer-Verlag 1975

Authors and Affiliations

  • E. Rodrigues-Pereira
    • 1
  • J. Wagner
    • 1
  1. 1.Pharmakologisches InstitutUniversitäts-Klinikum EssenEssen 1Federal Republic of Germany

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