Salbutamol: a new, selective beta-adrenoceptive receptor stimulant.

1. Salbutamol is a beta-adrenoceptive receptor stimulant. Its pharmacological actions are reduced or abolished by beta-receptor antagonists.2. In anaesthetized animals, salbutamol, given intravenously, was slightly less active than isoprenaline in preventing spasm of bronchial smooth muscle but was considerably less active as a cardiac stimulant and vasodepressor substance. Its duration of action was about 2 to 3 times that of isoprenaline.3. Salbutamol given by mouth or aerosol to conscious guinea-pigs, greatly diminished bronchospasm caused by inhalation of acetylcholine. By mouth, salbutamol was more active and had a longer duration than isoprenaline or orciprenaline without affecting heart rate. By aerosol, salbutamol was approximately 10 times as active as isoprenaline and 100 times as active as orciprenaline. Its duration of action was much longer than that of isoprenaline or orciprenaline. Only isoprenaline produced an increase in heart rate by the aerosol route.4. On isolated guinea-pig trachea salbutamol had about 1/10 the activity of isoprenaline, on isolated atria about 1/2000.