Inhaled adenosine and guanosine on airway resistance in normal and asthmatic subjects.

Abstract

4XY1 The airway response to the inhaled nucleosides, adenosine (6.7 x 10-4-6.7 mg/ml) and guanosine (7.3 x 10-4-1.4mg/ml) was studied in normal and asthmatic subjects.Airway response, measured in the body plethysmograph, was expressed as percentage change in specific airway conductance (sGaw) from baseline.2 Inhaled adenosine caused no change in sGaw in normal subjects but produced a dose-dependent reduction in sGaw in both allergic and non-allergic asthmatic subjects (76 and 62% reduction respectively at 6.7 mg/ml).3 Kinetics of adenosine induced bronchoconstriction were studied in 12 asthmatic subjects who inhaled a single concentration of adenosine.Bronchoconstriction was maximal within 5 min (42% reduction in sGaw) with partial recovery by 30 min. 4The related nucleoside guanosine caused no change in sGaw in normal or asthmatic subjects. 5Adenosine, but not guanosine, is a potent bronchoconstrictor in asthma suggesting that it may have a specific pharmacological effect.