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Non‐catechol phenylethanolamines: agonistic and antagonistic actions on β‐adrenoreceptors in isolated tissues from the guinea‐pig
Author(s) -
Malta E.,
Raper C.
Publication year - 1974
Publication title -
clinical and experimental pharmacology and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 103
eISSN - 1440-1681
pISSN - 0305-1870
DOI - 10.1111/j.1440-1681.1974.tb00548.x
Subject(s) - orciprenaline , isoprenaline , agonistic behaviour , receptor , terbutaline , chemistry , pharmacology , medicine , guinea pig , endocrinology , biology , stimulation , asthma , psychiatry , aggression
SUMMARY 1. Agonistic and antagonistic activities on β‐adrenoreceptors have been assessed for orciprenaline, terbutaline, soterenol and MJ7999–1 using isolated guinea‐pig atrial (β 1 ‐receptor) and tracheal (β 2 ‐receptor) preparations. 2. As agonists MJ7999–1 is more selective for β 2 ‐receptors than soterenol because of its increased activity in trachea, whereas terbutaline is more selective for β 2 ‐receptors than orciprenaline because of its decreased activity in atrial preparations. 3. Antagonistic activity was assessed from shifts in concentration‐effect curves to (‐)‐isoprenaline. 4. MJ7999–1 and soterenol possess competitive β‐receptor blocking actions in atrial (pA 2 ≈6.5) and tracheal (pA 2 ≈6.0) preparations. 5. Orciprenaline and terbutaline are relatively selective competitive β‐receptor antagonists, being more potent in atrial (pA 2 ≈6.3) than in tracheal (pA 2 ∼4.9) preparations. In atria non‐competitive antagonistic actions are apparent with these two drugs. 6. In rat vas deferens preparations only (‐)‐isoprenaline and soterenol display agonistic actions on α‐receptors. None of the compounds possesses α‐receptor antagonistic activity.