The purpose of this project is to explore the interaction between caffeine and dipyridamole on ischemia-reperfusion injury in the forearm.

Dipyridamole has been proven to reduce targeting of Annexin A5 in responses to ischemic exercise, indicating protection against ischemia-reperfusion injury in humans (pharmacological preconditioning). Dipyridamole increases the endogenous adenosine level by inhibition of the nucleoside transporter (ENT-1). Activation of the adenosine receptor protects against ischemia-reperfusion injury. We hypothesize that endogenous adenosine mediates the protective effect of dipyridamole against ischemia-reperfusion injury. Therefore the adenosine receptor antagonist caffeine will reduce the benefit of dipyridamole on forearm ischemia-reperfusion injury.

Inclusion Criteria:

• Male
• Age between 18-50yr.

Exclusion Criteria:

• cardiovascular disease
• hypertension (systole > 140 mmHg, diastole > 90 mmHg)
• hypercholesterolemia (random total cholesterol > 6.5 mmol/l)
• diabetes mellitus (fasting glucose > 7.0 mmol/L or random glucose > 11.0 mmol/L)
• asthma (recurrent episodes of dyspnea and wheezing, or usage of prescribed inhalation medication: i.e. corticosteroids or B2-agonists)
• participation in any clinical trial during the last 60 days prior to this study.
• administration of two doses of Annexin A5 (0,1mg; 450MBq) during the last 5 years prior to this study.