title: Response localization of the pharmacological agents histamine and salbutamol along the respiratory system by forced oscillations in asthmatic subjects.
abstract: The bronchodilating effect of 1 mg and 0.4 mg salbutamol on the impedance of the respiratory system was studied in 25 asthmatic subjects after histamine-induced bronchoconstriction. Histamine caused an increase of respiratory resistance (Rrs) at lower frequencies and a frequency dependence of Rrs. Respiratory reactance (Xrs) decreased at all frequencies after histamine challenge. These changes can be explained by peripheral airway obstruction. Impedance measurements performed 5 min after inhalation of 1 mg and 0.4 mg salbutamol showed a decrease of Rrs values at lower frequencies, a disappearance of the frequency dependence of Rrs, and a significant increase of Xrs values. No significant differences in absolute changes of Rrs and Xrs are observed between the salbutamol regimens. These changes after inhalation of salbutamol can be explained by supposing a predominant action on the peripheral airways.
authors.affiliation: Department of Pulmonary Diseases, University of Limburg, Maastricht, The Netherlands.
authors.forename: E F
authors.initials: EF
authors.lastname: Wouters
authors.forename: A H
authors.initials: AH
authors.lastname: Polko
authors.forename: B F
authors.initials: BF
authors.lastname: Visser
mesh_terms: D000328:Adult; D000403:Airway Resistance / Q000187:drug effects*; D000420:Albuterol / Q000494:pharmacology*; D001249:Asthma / Q000188:drug therapy* / Q000503:physiopathology; D001985:Bronchial Provocation Tests; D005260:Female; D005541:Forced Expiratory Volume / Q000187:drug effects; D006632:Histamine / Q000494:pharmacology*; D006801:Humans; D008297:Male; D009991:Oscillometry
chemical_list: D006632:Histamine; D000420:Albuterol