The most powerful protective mechanism against ischemia-reperfusion injury other than rapid
reperfusion is ischemic preconditioning. Ischemic preconditioning is defined as the
development of tolerance to ischemia-reperfusion injury by a previous short bout of ischemia
resulting in a marked reduction in infarct size. This mechanism can be mimicked by several
pharmacological substances such as adenosine and morphine.
We, the researchers at Radboud University Nijmegen Medical Centre, have recently developed a
method in which we can detect ischemia-reperfusion injury in the human forearm by using
Annexin A5 scintigraphy (Rongen et al). With this method we will determine whether opioid
receptors are involved in ischemic preconditioning. We expect to find that morphine can mimic
ischemic preconditioning and that acute ischemic preconditioning can be blocked with the
opioid receptor antagonist naloxon. This study will increase our knowledge about the
mechanism of ischemic preconditioning and may also provide leads to exploit this endogenous
protective mechanism in a clinical setting.