Effect of purine nucleosides on the contractile function of the rat heart in ischemia and reperfusion

: The Langendorf isolated rat hearts underwent 30-minute total ischemia followed by 60-minute reperfusion. Adenosine, inosine or guanosine was added at a concentration of 50 mumol/l into the perfusate in the first 30 minutes. The nucleotides significantly increased the developed pressure and the maximum left ventricular contractility rate. The most effective agent was adenosine which also made blood flow higher. Guanosine was more effective than adenosine and inosine in protecting the heart from ischemic contracture. At the same time adenosine augmented the arrhythmogenic effect of reperfusion, by significantly elevating the cardiac levels of diene conjugates and malonic dialdehyde. It is suggested that the arrhythmogenic effect of adenosine is the result of activated lipid peroxidation due to adenosine exchange via the xanthine reaction during nucleotide-induced vasodilation.