Description_x000D_ Packaging_x000D_ 5, 25 mg in glass bottle_x000D_ Biochem/physiol Actions_x000D_ MRS1220 is a putative A3 adenosine receptor antagonist. MRS 1220 was found to be competitive in saturation binding studies using the agonist radioligand 125I AB-MECA at cloned human brain A3 receptors expressed in HEK-293 cells. Antagonism was demonstrated in functional assays consisting of agonist-induced inhibition of adenylate cyclase and the stimulation of binding of 35S guanosine 5′-O-(3-thiotriphosphate (35S GTP-gamma-S) to the associated G-proteins. MRS 1220 and MRS 1191, with KB values of 1.7 and 92 nM, respectively, proved to be highly selective for human A3 receptor vs human A1 receptor-mediated effects on adenylate cyclase. In addition, MRS 1220 reversed the effect of A3 agonist-elicited inhibition of tumor necrosis factor-alpha formation in the human macrophage U-937 cell line, with an IC50 value of 0.3 μM._x000D_ Features and Benefits_x000D_ This compound is featured on the Adenosine Receptors page of the Handbook of Receptor Classification and Signal Transduction. To browse other handbook pages, click here.