Enhancement of adenosine‐induced relaxant responses of the guinea‐pig isolated taenia coli and aortae by a novel nootropic agent BY‐1949: comparison with dipyridamole

Abstract— In muscle strips of guinea‐pig taenia coli and aortae, the effects of 3‐methoxy‐1 1‐methyldibenz[b,f][1,4]oxazepine‐8‐carboxylate (BY‐1949) on the relaxant response to adenosine have been compared with those of dipyridamole. BY‐1949 (3 × 10−5–10−4 M) as well as dipyridamole (3 × 10−7–10−5 M) resulted in a significant potentiation of relaxant responses to a cumulative administration of adenosine (10−6–10−3 M), but the drugs did not affect the response to noradrenaline and acetylcholine. The results indicate that BY‐1949 exerts a selective potentiating effect on reactivity to exogenous adenosine.