Studies on the effects of enantiomers of soterenol, trimetoquinol and salbutamol on beta adrenergic receptors of isolated guinea-pig atria and trachea.

摘要: Beta adrenergic receptors of guinea-pig atria and trachea were investigated with enantiomers tissue selective agonists: soterenol, trimetoquinol salbutamol. If the these two tissues are different, ratio potencies between agonists should reflect unique asymmetries receptors. From trachea, enantiomeric potency differences (in log units) are: for 1.86 2.19; trimetoquinol, 1.61 1.56 salbutamol, 2.19, respectively. both tissues, values each pair isomers identical. Analysis selectivity from reveals that (—)-isomers are, respectively, 3.3-, 9- 24-fold more potent in than atria. However, when compared to (—)-isoproterenol on a relative basis tissue, only salbutamol is shown have any degree trachea. When activities atria, soterenol appear as "partial agonists" while produces about 90% maximum effect isoproterenol. All produce same effects In sotalol blocks greater extent it isoproterenol trimetoquinol. It suggested factors other ligand binding modes receptor could account observations. The data support previous suggestions agonist sites beta may be similar. Tissue different requirements access or intrinsic