Activation of P2X7 receptors inhibits DNA synthesis induced by EGF and PDGF in addition to FGF2. Quiescent cultures of rat cortical astrocytes were treated with FGF2 (25 ng/ml), EGF (10 ng/ml), or PDGF (2.5 ng/ml), alone or in combination with BzATP (100 uM), and DNA synthesis was measured as described in Materials and Methods. H3-Thymidine incorporation in control cultures was 30,376 ± 4257 cpm/mg protein (Mean ± SEM, n = 3). Activation of P2X7 receptors significantly inhibited DNA synthesis induced by EGF, PDGF and FGF2 (* p < 0.05).