Adenosine modulates endothelin-induced bronchoconstriction in guinea pig airway

The present study was designed to determine whether endogenous and exogenous adenosine modulates endothelin (ET)-induced bronchoconstriction. Exogenous adenosine enhances ET-induced bronchoconstriction. Following pretreatment with adenosine deaminase and theophylline to eliminate or antagonize endogenous adenosine, ET-1-induced bronchoconstriction was significantly attenuated, but not that of ET-3. In conclusion, this is the first report of an enhancement of ET-induced bronchoconstriction of guinea pig airways by endogenous and exogenous adenosine. Our findings may be useful in designing specific adenosine receptor antagonists as therapeutic agents in the management of bronchial asthma.