Release of adenosine from rat lung by antigen and compound 48/80

The mechanism by which theophylline inhibits anaphylactic constriction of the airways is not known (Bowman & Rand 1980). Part of its activity may be due to inhibition of cyclic nucleotide breakdown, part to antagonism of endogenous adenosine since theophylline is a potent inhibitor of adenosine actions in therapeutic concentrations of the drug (Fredholm 1980). Adenosine is known to potentiate mediator release from mast cells (Marquardt et al. 1978, Fredholm & Sydbom 1980) and it antagonizes the direct tracheorelaxant effect of theophylline (Fredholm et al. 1979). I have examined the possibility that lung is capable of releasing adenosine and that the release is enhanced by anaphylactic and pseudoanaphylactic reactions.