The bronchial effects of adenosine in the rat.

The in vivo intravenous administration of adenosine caused bronchoconstriction in the rat. There were significant differences between inbred rat strains with regard to bronchial reactivity to adenosine. Inosine caused bronchoconstriction in the rat but was a less potent bronchoconstrictor than adenosine and there was no correlation between the bronchial reactivity to inosine and the reactivity to adenosine. Theophylline, DSCG and nedocromil were potent inhibitors of the adenosine-induced bronchoconstriction. Bilateral vagotomy and the ganglion blocker hexamethonium had no effect on the adenosine-induced bronchoconstriction. High doses of atropine had a small inhibitory effect. The bronchial adenosine receptor has the characteristics of the A2 type.