Evaluation of the cough reflex and airway reactivity in toluene- and ovalbumin-induced airway hyperresponsiveness.

Abstract

Stimulation of mechanoceptors is considered to be the major mechanism of cough. Our aim in this study was to evaluate the relationship between in vivo and in vitro airway reactivity (AR) in chemically- and antigen-induced airway hyperresponsiveness (AHR). AHR was induced chemically (toluene vapors) or via antigen (ovalbumin) in healthy guinea pigs. While toluene inhalation did not cause a significant difference in the number of cough efforts during citric acid nebulization, a significant increase in specific airway resistance after inhalation of histamine was observed, as measured in double chamber body plethysmograph. In contrast, ovalbumin led to a significant increase in both the number of cough efforts and in vivo AR. The in vitro tests confirmed the presence of increased reactivity of tracheal and lung tissue strips to histamine. However, no clear correlation between bronchoconstriction and cough reflex was found in the experimental model used for this study.