title: Contribution of β-adrenergic receptors to exercise-induced bronchodilatation in healthy humans.
abstract: Exercise in healthy subjects is usually associated with progressive bronchodilatation. Though the decrease in vagal tone is deemed to be the main underlying mechanism, activation of bronchial β(2)-receptors may constitute an additional cause. To examine the contribution of β(2)-adrenergic receptors to bronchodilatation during exercise in healthy humans, we studied 15 healthy male volunteers during maximum exercise test at control conditions and after a non-selective β-adrenergic blocker (carvedilol 12.5mg twice a day until heart rate decreased at least by 10beats/min) and inhaled β(2)-agonist (albuterol 400μg). Airway caliber was estimated from the partial flow at 40% of control forced vital capacity (V˙(part40)) and its changes during exercise from the slope of linear regression analysis of V˙(part40) values against the corresponding minute ventilation during maximal exercise until exhaustion. At control, V˙(part40) increased progressively and significantly with exercise. After albuterol, resting V˙(part40) was significantly larger than at control increased but did not further increase during exercise. After carvedilol, V˙(part40) was similar to control but its increase with exercise was significantly attenuated. These findings suggest that β(2)-adrenergic system plays a major role in exercise-induced bronchodilation in healthy subjects.
authors: Allergologia, Fisiopatologia Respiratoria, ASO S. Croce e Carle, 12100 Cuneo, Italy.
authors: Andrea
authors: A
authors: Antonelli
authors: Roberto
authors: R
authors: Torchio
authors: Luca
authors: L
authors: Bertolaccini
authors: Alberto
authors: A
authors: Terzi
authors: Fabrizio
authors: F
authors: Rolfo
authors: Piergiuseppe
authors: P
authors: Agostoni
authors: Carlo
authors: C
authors: Gulotta
authors: Vito
authors: V
authors: Brusasco
authors: Riccardo
authors: R
authors: Pellegrino
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000420:Albuterol / Q000494:pharmacology; D001993:Bronchodilator Agents / Q000494:pharmacology; D002227:Carbazoles / Q000494:pharmacology; D000077261:Carvedilol; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D006801:Humans; D008297:Male; D008875:Middle Aged; D009129:Muscle Tonus / Q000187:drug effects / Q000502:physiology; D009130:Muscle, Smooth / Q000187:drug effects / Q000502:physiology; D011412:Propanolamines / Q000494:pharmacology; D012123:Pulmonary Ventilation / Q000187:drug effects / Q000502:physiology*; D011943:Receptors, Adrenergic, beta / Q000378:metabolism*; D012129:Respiratory Function Tests
chemical_list: D000319:Adrenergic beta-Antagonists; D001993:Bronchodilator Agents; D002227:Carbazoles; D011412:Propanolamines; D011943:Receptors, Adrenergic, beta; D000077261:Carvedilol; D000420:Albuterol