Adenosine (
ADO) has a cardioprotective effect in
ischemia-reperfusion injury when administered both prior to
ischemia and during reperfusion.
ADO has also been implicated in the mechanism of ischemic pre-conditioning. The aim of this study was to investigate whether there was a concentration-response between the administration of
ADO prior to
ischemia-reperfusion and reduction in subsequent
infarct size. Rabbit isolated perfused hearts were subjected to 45 min
ischemia and 180 min reperfusion following pre-treatment with either
Krebs Henseleit buffer alone or
buffer containing
ADO at a range of concentrations (3 micro M-100 micro M) for 5 min followed by 5 min perfusion with
buffer.
Infarct/risk ratios were significantly reduced in hearts pre-perfused with higher (> 3 micro M) concentrations of
ADO (Control, 58.5 +/- 1.5%; 3 micro M
ADO, 51.6 +/- 3.0% ; 6 micro M
ADO, 44.1% +/- 2.0%; 10 micro M
ADO, 33.3 +/- 1.9%; 20 micro M
ADO, 26.6 +/- 0.9%; 50 micro M
ADO, 21.6 +/- 3.5%; 100 micro M
ADO, 23.0 +/- 0.6%). We conclude that pre-treatment with
ADO leads to a concentration-dependent reduction in
infarct size.