The role of alpha-receptors in bronchoconstriction induced by beta-blockade.
We examined 10 patients with an exercise-induced asthma. Physical exercise was carried out under placebo, 40 mg propranolol, 5 mg pindolol and 50 mg metoprolol, respectively, before and after alpha blockade. After exercise, we noted a distinct increase of airway resistance in all cases, the increase of which, however, was lower after a preceding alpha blockade. Under propranolol, the increase of the airway resistance and of norepinephrine, as compared with pindolol, metoprolol, and placebo, was most intensive.
D000319:Adrenergic beta-Antagonists / Q000494:pharmacology*; D000328:Adult; D000403:Airway Resistance / Q000187:drug effects; D001250:Asthma, Exercise-Induced / Q000503:physiopathology; D001982:Bronchial Diseases / Q000139:chemically induced / Q000503:physiopathology*; D003251:Constriction, Pathologic; D005260:Female; D006801:Humans; D008297:Male; D009638:Norepinephrine / Q000097:blood; D005082:Physical Exertion; D011941:Receptors, Adrenergic / Q000502:physiology*; D011942:Receptors, Adrenergic, alpha / Q000502:physiology*; D012146:Rest
D000319:Adrenergic beta-Antagonists; D011941:Receptors, Adrenergic; D011942:Receptors, Adrenergic, alpha; D009638:Norepinephrine