NECA-induced reduction of ERK1/2 phosphorylation and effect of adenosine receptor antagonists.

The nonselective antagonist EFA (10 μM) blocked the NECA (100 nM) effect (A) and so did DPCPX at 10 μM, a concentration high enough to block A2BAR (B). In contrast, the A2A selective antagonist SCH 58261 (C) and the A3 selective antagonist MRS 1220 (D), both at 10 μM, had no effect. Western blots show a representative experiment, the columns represent mean values of n = 8 (A), 6 (B), 4 (C), and 5 (D) independent experiments (* p < 0.001, significantly different from control).