β-Adrenergic receptor blocking properties of three allyl-substituted phenoxypropanolamines

Three phenoxypropanolamines with allyl-substitution in the three positions of the benzene ring were studied in the isolated guinea pig atrium and trachea and on heart rate and peripheral vascular resistance in the anaesthetized cat. The ortho- and meta-allyl compounds blocked all responses to isopreneline to about an equal degree. The para-allyl derivative however, showed markedly higher affinity to the β-receptors of the heart than to those of vascular and tracheal smooth muscle.