title: Comparison of in vivo and in vitro responses to histamine in human airways.
abstract: The study was designed to compare in vivo responses to histamine in 14 patients prior to thoracotomy with in vitro responses to histamine of both parenchymal and bronchial tissue. Although a wide range of responsiveness occurred in vivo, as measured by the histamine inhalation test, the variation in the in vitro dose-response curves was negligible. There was no correlation between the dose of histamine that resulted in a 20% reduction in forced expiratory volume in one second and the concentration of histamine producing 50% of the maximal response in vitro. These findings raise the possibility that airway hyperresponsiveness may not result from an intrinsic abnormality of airway smooth muscle.
mesh_terms: D000328:Adult; D000368:Aged; D001980:Bronchi / Q000502:physiology*; D005260:Female; D006636:Histamine Release; D006801:Humans; D008168:Lung / Q000502:physiology*; D008297:Male; D008875:Middle Aged