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Ozone induces impairment of adrenergic relaxation in thoracic guinea pig tracheas

The effect of ozone on airway relaxation mechanisms has been seldom studied. We exposed guinea pigs to ozone (0.3, 0.6 or 1.2 ppm for 4 h) and studied the in vitro tracheal responses to isoproterenol and nitroprusside, looking for differences between cervical and thoracic regions. We found that ozone did not alter responses to nitroprusside, whereas it produced a concentration‐dependent decrease in the responses to isoproterenol in thoracic but not cervical tracheas. Thus, in isolated organ studies care should be taken to avoid mixing cervical and thoracic tracheal regions, at least when adrenergic responses are to be evaluated. Copyright © 2001 John Wiley & Sons, Ltd.