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.

In muscle strips of guinea-pig taenia coli and aortae, the effects of 3-methoxy-11-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 x 10(-5)-10(-4) M) as well as dipyridamole (3 x 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.