| 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. A1AR is widely distributed and has been well characterized. High expression of A1AR is found in brain, dorsal horn of the spinal cord, adrenal gland, and atria, and other tissues including adipose, colon, and kidney. A1AR is the most prominent adenosine receptor in adipocytes and has become a target for research on obesity. A possible role in cell proliferation and carcinogenesis has also been suggested for A1AR. |
