title: Adrenergic airway vascular smooth muscle responsiveness in healthy and asthmatic subjects.
abstract: The purpose of the present study was to determine the responsiveness of airway vascular smooth muscle (AVSM) as assessed by airway mucosal blood flow (Qaw) to inhaled methoxamine (alpha(1)-agonist; 0.6-2.3 mg) and albuterol (beta(2)-agonist; 0.2-1.2 mg) in healthy [n = 11; forced expiratory volume in 1 s, 92 +/- 4 (SE) % of predicted] and asthmatic (n = 11, mean forced expiratory volume in 1 s, 81 +/- 5%) adults. Mean baseline values for Qaw were 43.8 +/- 0.7 and 54.3 +/- 0.8 microl. min(-1). ml(-1) of anatomic dead space in healthy and asthmatic subjects, respectively (P < 0.05). After methoxamine inhalation, the maximal mean change in Qaw was -13.5 +/- 1.0 microl. min(-1). ml(-1) in asthmatic and -7.1 +/- 2.1 microl. min(-1). ml(-1) in healthy subjects (P < 0.05). After albuterol, the mean maximal change in Qaw was 3.0 +/- 0.8 microl. min(-1). ml(-1) in asthmatic and 14.0 +/- 1.1 microl. min(-1). ml(-1) in healthy subjects (P < 0.05). These results demonstrate that the contractile response of AVSM to alpha(1)-adrenoceptor activation is enhanced and the dilator response of AVSM to beta(2)-adrenoceptor activation is blunted in asthmatic subjects.
authors.affiliation: Division of Pulmonary and Critical Care Medicine, University of Miami School of Medicine at Mount Sinai Medical Center, Miami Beach, Florida 33140, USA.
authors.forename: J
authors.initials: J
authors.lastname: Brieva
authors.forename: A
authors.initials: A
authors.lastname: Wanner
mesh_terms: D000280:Administration, Inhalation; D000316:Adrenergic alpha-Agonists / Q000008:administration & dosage / Q000494:pharmacology*; D000318:Adrenergic beta-Agonists / Q000008:administration & dosage / Q000494:pharmacology*; D000328:Adult; D000420:Albuterol / Q000008:administration & dosage* / Q000494:pharmacology; D001249:Asthma / Q000503:physiopathology*; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D008168:Lung / Q000098:blood supply / Q000503:physiopathology; D008297:Male; D008729:Methoxamine / Q000008:administration & dosage / Q000494:pharmacology*; D008875:Middle Aged; D009131:Muscle, Smooth, Vascular / Q000294:innervation* / Q000503:physiopathology; D011652:Pulmonary Circulation; D012126:Respiratory Dead Space; D020545:Respiratory Mucosa / Q000098:blood supply; D014661:Vasoconstriction; D014664:Vasodilation
chemical_list: D000316:Adrenergic alpha-Agonists; D000318:Adrenergic beta-Agonists; D008729:Methoxamine; D000420:Albuterol