Journal of toxicology and environmental health
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J Toxicol Environ Health · Nov 1992
Comparative StudyInduction of transient airway hyperresponsiveness by exposure to 4 ppm nitrogen dioxide in guinea pigs.
In the present study, we investigated (1) whether airway responsiveness to inhaled histamine-aerosol could be induced during 7-d exposure of guinea pigs to 4 ppm NO2 and, if so, (2) whether thromboxane A2 may be involved in such increase. Female Hartley guinea pigs were divided into 6 groups (n = 15/group). Three groups were exposed to filtered air and the other 3 groups were exposed to NO2 for 1, 3, or 7 d (24 h/d). ⋯ Exposure to air had no significant effect on the airway responsiveness. This transient hyperresponsiveness was inhibited by a specific inhibitor of thromboxane synthetase, OKY 046. These results indicated that (1) a lower concentration (4 ppm) of NO2 than that previously reported can induce transient hyperresponsiveness in guinea pigs during appropriate long-term exposure, and (2) thromboxane A2 may play an important role in this transient airway hyperresponsiveness.