Effect of beta-adrenergic blockers on isolated coronary arterial strip and tracheal smooth muscle of pig.
Isolated coronary arterial strip and tracheal smooth muscle of pig, containing predominantly beta 1- and beta 2-adrenoceptors respectively, have been used for estimating the comparative potency of nine beta-adrenergic blocking agents. The order of potency of the antagonists on the isolated coronary arterial strip was propranolol greater than alprenolol greater than H 64/52 greater than H 64/55 greater than practolol greater than H 87/07 greater than atenolol greater than metoprolol greater than H 35/25, whilst the order of potency on the pig tracheal smooth muscle was alprenolol greater than propranolol greater than H 35/25 greater than H 87/07 greater than H 64/55 greater than H 64/52 greater than metoprolol greater than practolol greater than atenolol. Propranolol and alprenolol were almost equipotent in both the preparations and hence were nonspecific. Although practolol, metoprolol, H 64/55 and H 87/07 were beta 1-selective, their selectivity ratio was comparatively smaller than that of atenolol and H 64/52. The study indicates that H 64/52 and atenolol are the most specific beta-adrenergic blocking agents on isolated coronary arterial strip of pig and that their beta 1/beta 2-ratios are 126 and 120 respectively. H 64/52 like atenolol may be of therapeutic value in cardiovascular disorders.
D000319:Adrenergic beta-Antagonists / Q000494:pharmacology*; D000818:Animals; D003331:Coronary Vessels / Q000187:drug effects; D066298:In Vitro Techniques; D009119:Muscle Contraction / Q000187:drug effects*; D009130:Muscle, Smooth / Q000187:drug effects*; D009928:Organ Specificity; D013552:Swine; D014132:Trachea / Q000187:drug effects
D000319:Adrenergic beta-Antagonists