| Scientific Background: | Adenosine is an endogenous nucleoside generated locally in tissues under conditions of hypoxia, ischemia, or inflammation. It modulates a variety of physiological functions in many tissues including brain and heart. It exerts its action via four specific adenosine receptors (also named P1 purinergic receptors): A1 Adenosine Receptor (A1AR), A2A Adenosine Receptor (A2AAR), A2B Adenosine Receptor (A2BAR), and A3 Adenosine Receptor (A3AR). All are integral membrane proteins and members of the G Protein-Coupled Receptor superfamily. The various adenosine receptors can be distinguished on the basis of their differential selectivity for adenosine analogs. Expression of A3AR has been reported in brain, kidney, liver, and heart. It plays a role in modulation of cerebral ischemia, asthma, and cell growth. In addition, it may have a cardioprotective role for A3AR. Expression of A3AR was reported to be elevated in cancerous tissues as well as in auto-immune inflammatory diseases. |
