Modeling the acute- and late-phase responses to peripheral airway cooling and desiccation.
Acute bronchoconstriction after isocapnic hyperpnea can be produced in most asthmatic individuals. However, the existence of a late-phase response is less certain. We used a canine model of isocapnic hyperpnea to test the hypothesis that this discrepancy is due to differences in the challenge threshold for the responses. Acute-phase and late-phase bronchoconstriction was measured in nine dogs after peripheral airway exposure to unconditioned air. Additionally, bronchoalveolar lavage fluid (BALF) was obtained during the late-phase response. The acute-phase response was a polynomial function with a decreasing slope at higher challenges, whereas the late-phase response suggested that a minimum threshold of challenge severity was needed to produce late-phase bronchoconstriction. BALF leukocyte and eicosanoid concentrations had linear relationships with challenge severity. Our data support the hypothesis that acute- and late-phase posthyperpnea responses have different dose-response relationships, a fact that may explain the frequent lack of a late-phase response. However, our data suggest that mild inflammation can be induced with relatively lower challenge severity.
Davis
Michael S
MS
Department of Physiological Sciences, Oklahoma State University, Stillwater 74078, USA. msdavis@okstate.edu
Royer
Chris M
CM
Payton
Mark
M
Buttress
Brian
B
D000210:Acute-Phase Reaction / Q000503:physiopathology*; D000403:Airway Resistance / Q000502:physiology; D000818:Animals; D001980:Bronchi / Q000098:blood supply / Q000502:physiology*; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry / Q000166:cytology; D016084:Bronchoconstriction / Q000502:physiology*; D001999:Bronchoscopy; D003080:Cold Temperature / Q000009:adverse effects*; D003890:Desiccation; D004285:Dogs; D015777:Eicosanoids / Q000378:metabolism; D006813:Humidity; D007962:Leukocytes / Q000502:physiology; D008954:Models, Biological; D012039:Regional Blood Flow / Q000502:physiology
D015777:Eicosanoids