A-740003 is a potent, selective and competitive antagonist of P2X7 receptor with IC50 of 18 nM and 40 nM for rat and human P2X7 receptors, respectively. A-740003 potently blocks agonist-evoked IL-1β release and pore formation with IC50 of 156 nM and 92 nM in differentiated human THP-1 cells.