Figure 1.

Relative potency of adenosine receptor agonists to relax rabbit cranial mesenteric arteries. The mesenteric artery rings were pre-contracted with noradrenaline (10 μM) and the functionality of the endothelium was verified by testing the response to acetylcholine. Then, cumulative concentration-response curves with increasing concentrations of the selective A_2A receptor agonist, CGS 21680, of the mixed A₁/A₂ receptor agonist, NECA, or with the closest non-metabolizable adenosine analogue, CADO, were carried out in (a). In (b), cumulative concentration-response curves with increasing concentrations of CADO were performed either in the absence or in the presence of the selective A_2A receptor antagonist, ZM 241385 (100 nM). The data are mean±s.e.mean of 5 – 6 experiments.