Jpn. J. Pharmacol. 83 (4), 348-350 (2000)

Acute Desensitization of Adenosine by Adenosine Infusion in Isolated Dog Atria

Masato Tsuboi and Shigetoshi Chiba

Department of Pharmacology, Shinshu University School of Medicine, Matsumoto 390-8621, Japan

Abstract: We investigated the effects of a continuous infusion of adenosine on responses of sinus rate and developed tension to bolus injections of adenosine and acetylcholine in isolated, blood-perfused canine right atria. Each drug was directly injected into the sinus node artery of the isolated atrium. During adenosine infusions, the negative chronotropic and inotropic responses to bolus injections of adenosine were significantly inhibited in a dose-related manner, while the negative responses to administered acetylcholine were consistently potentiated. These results indicate that adenosine infusion has an acute desensitizing action on subsequent bolus adenosine, although the cholinergic action is enhanced by a continuous infusion of adenosine.

Keywords: Adenosine infusion, Dog right atria, Desensitization

Copyrightę The Japanese Pharmacological Society 2000

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