Abstract
The isolated right atrium of the dog was perfused with blood led from a support dog. The selective injection of dipyridamole into the sinus node artery at a dose of 1-10 μg induced a slight negative chronotropic and positive inotropic effect. The administration of 0.3-10 μg of adenosine caused a negative chronotropic and inotropic effect. The effects induced by adenosine were potentiated by a single injection or a continuous infusion of dipyridamole usually in the duration of adenosine action and frequently in the maximum decreases of the atrial rate and developed tension.
