NF 449 is a selective Gsα-subunit G-protein antagonist which reduces the association rate of guanosine 5'-[γ-thio]triphosphate ([35S]GTP[γS]) binding to Gα s -s (Gs&alpha-s) and inhibits the stimulation of adenylyl cyclase activity in S49 cyc- membranes. In addition, NF 449 interferes with binding between the Adenosine A1-R (A1-adenosine receptor) and its cognate G proteins (Gi/Go). Alternate studies suggest that NF449 inhibits a wide array of P2 receptors such as P2X3, P2Y1, and P2Y2, while showing the highest selectivity towards P2X1. Furthermore, NF449 can disrupt the coupling of β-AR (β-adrenergic receptors).