Effects of adenosine A1 receptor agonist CCPA and antagonist DPCPX on ischemia/reperfusion-induced arrhythmias in rats

Aim: Adenosine has been commonly used to treat supraventricular tachycardia in clinics. However, there are only a few studies on the effects of adenosine on ischemia or reperfusion induced arrhythmia and they conflict with the results of the present study. During this study, we aimed to clarify the effect of adenosine on ischemia-reperfusion induced arrhythmia.Materials and methods: Left coronary artery was ligated for 6 min and it was released for 15 min to produce reperfusion.A1 adenosine agonist CCPA (2 Chloro - N6 – Cyclopentyl-adenosine), and A1 selective antagonist DPCPX (8 –Cyclopentyl - 1,3 -dipropylxanthine) in 5 µg/kg dose alone and in combination were given intravenously before ligation,at the second minute of the ligation and just following the reperfusion. Results: Adenosine given only at the second minute of the ligation is found to decrease the total duration of arrhythmia observed in the reperfusion stage. DPCPX given in this period is found to block the antiarrhythmic effect of adenosine.Adenosine given after reperfusion and before ligation was not effective in decreasing reperfusion induced arrhythmia. Conclusion: The time dependent effect of the administration during ischemia and reperfusion was important for the effect of adenosine. The present study showed that antiarrhythmia produced by adenosine is related to the activation of A1 adenosine receptor.