In a mode of ventricular arrhythmia (S)-Alprenolol was administered to dogs intravenously at 0.5 - 8.0 mg/kg.

Guinea-pig spontaneously beating right atria and tracheal strips were suspended in water-jacketed 10ml tissue baths containing a physiological salt solution. Atria were allowed to equilibrate for 1 hr before any drugs were added. Responses from both tissues were recorded on a Grass polygraph and atrial rates were monitored via 7P4A tachographs. Carbachol (3 × 10 -7 M) was used to induce tone in tracheal strips and added to the bath 15 min prior to determining the relaxing effects of the drug. Selected concentrations of the antagonists were allowed to interact with each tissue for 3, 10, 25, 45, 65, or 120 min before addition of the agonist. All concentrations of antagonists were added in a volume of 0.1 ml.