Subject(s)

Adult , Middle Aged , Male , Female , Humans , Asthma/physiopathology , Histamine/administration & dosage , Ipratropium/administration & dosage , Methacholine Compounds/administration & dosage , Bronchial Provocation Tests , Forced Expiratory Volume , Vagus Nerve/physiopathology , Double-Blind Method , Clinical Trials as Topic , Dose-Response Relationship, Drug