title: Role of purinergic system in tracheobronchial reactivity of healthy and bronchopathic subjects.
abstract: We have investigated the effect of inhaled adenosine on bronchomotor tone in 16 healthy and 24 allergic and non-allergic bronchopathic subjects. We determined the inhaled adenosine dose-response curves after no treatment and after treatment with aminophylline (240 mg in 10 min), reproterol (90 mcg in 2 min) and salbutamol (100 mcg in 2 min) administered intravenously 15 min before adenosine and reproterol (500 mcg) and salbutamol (200 mcg) administered by inhalation from a metered aerosol 30 min before adenosine on separate days. Without prior treatment, inhaled adenosine caused bronchoconstriction in both groups of subjects (normal, and atopic and non-atopic asthmatic ones), but the peripheral airways revealed only a moderate change in normal subjects. Aminophylline caused a greater inhibition of adenosine bronchoconstriction than did reproterol. These results suggest that inhaled adenosine bronchoconstriction involved purinergic transmission and that it is mediated via a P1/Ri (A-1/R1) receptor. Aminophylline is a potent antagonist at purinoceptor level. Reproterol inhibits bronchoconstriction by a mechanism independent of its effect on beta-adrenergic receptors. Because salbutamol, i.e. a beta 2-agonist bronchodilator, did not inhibit adenosine-induced bronchoconstriction (or very nearly so), our results support the view that reproterol antagonizes P1/Ri (A1/R1) tracheobronchial receptors.
authors.affiliation: Department of Pharmacology and Toxicology, 1st Faculty of Medicine and Surgery, University of Naples, Italy.
authors.forename: V
authors.initials: V
authors.lastname: Susanna
authors.forename: A
authors.initials: A
authors.lastname: Loffreda
authors.forename: M G
authors.initials: MG
authors.lastname: Matera
authors.forename: R
authors.initials: R
authors.lastname: Servodio
authors.forename: A
authors.initials: A
authors.lastname: Filippelli
authors.forename: A
authors.initials: A
authors.lastname: Santagata
authors.forename: C
authors.initials: C
authors.lastname: Montanaro
authors.forename: N
authors.initials: N
authors.lastname: Carapella
authors.forename: E
authors.initials: E
authors.lastname: Marmo
mesh_terms: D000241:Adenosine / Q000494:pharmacology; D000293:Adolescent; D000328:Adult; D000368:Aged; D000420:Albuterol / Q000494:pharmacology; D000628:Aminophylline / Q000494:pharmacology; D001249:Asthma / Q000503:physiopathology; D001980:Bronchi / Q000187:drug effects / Q000502:physiology*; D001991:Bronchitis / Q000503:physiopathology; D001993:Bronchodilator Agents / Q000494:pharmacology; D002648:Child; D004338:Drug Combinations; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D008297:Male; D009921:Metaproterenol / Q000031:analogs & derivatives / Q000494:pharmacology; D008875:Middle Aged; D011983:Receptors, Purinergic / Q000187:drug effects / Q000502:physiology*; D013806:Theophylline / Q000031:analogs & derivatives / Q000494:pharmacology; D014132:Trachea / Q000187:drug effects / Q000502:physiology*
chemical_list: D001993:Bronchodilator Agents; D004338:Drug Combinations; D011983:Receptors, Purinergic; C014792:reproterol; D000628:Aminophylline; D009921:Metaproterenol; D013806:Theophylline; D000241:Adenosine; D000420:Albuterol