Differences in Chronotropic and Dromotropic Responses of the SA and AV Nodes to Adenosine and Acetylcholine

Abstract

It is well known that adenosine produces a deceleration of sinus rate though not so prominent while a high grade AV block is seen in the guinea-pig. In the dog the sinus rate is so considerably retarded by adenosine that the action upon the AV conduction is not appreciated on rough examination (Drury and Szent-Gyorgyi 1929) (1). In the present study, selective perfusion systems of the sinus and AV node arteries were arranged (2). The double perfusion method has been described in a previous paper (3). Effects of adenodine on the AV conductivity in comparison with those on the automaticity of the SA or AV node were examined.