A NEW BETA-2-ADRENOCEPTOR AGONIST WITH ALPHA-1-ADRENOCEPTOR BLOCKING PROPERTIES

  • 1 January 1981
    • journal article
    • research article
    • Vol. 48  (4) , 340-348
Abstract
The phenylethanolamine D2343 exhibits a dualistic adrenoceptormediated effect, i.e., a .beta.-agonistic effect combined with an .alpha.-antagonistic one. Tracheal smooth muscles and heart preparations were used to gauge the agonistic effect on adrenergic .beta.-receptors. Rabbit aorta and rat vas deferens were used to determine the .alpha.-adrenoceptor blocking activity. The .beta.-adrenoceptor activity of D2343 was classified as .beta.2-type with about the same efficacy as the .beta.2-selective terbutaline on tracheal muscle. The effect on isolated heart preparations was greater than that produced by terbutaline. The .alpha.-receptor blocking capacity was directed against the .alpha.1-receptor type and was of nearly the same potency as for phentolamine.