Abstract
Not only cyclic 3'. 5'-AMP but also related compounds containing adenosine moiety potentiated the contractile response of the isolated guinea-pig vas deferens to catecholamines, especially to dl-isoproterenol. The potentiating activity of cyclic 3', 5'-AMP was one-tenth that of adenosine or 5'-AMP. From these findings, it is suggested that not only adenosine moiety but also the steric conformation of adenine mononucleotides play an important role in potentiating the contractile response to catecholamines, and that the potentiation phenomenon occurs on the cell membrane. On the other hand, theophylline reduced the contractile response especially to dlisoproterenol and counteracted the potentiation phenomenon caused by cyclic 3', 5'AMP or adenosine. Possible mechanisms of action are discussed.
