Effects of NMDAR inhibition on the rescue of ERK1/2 phosphorylation by heme. A, Cortical neurons treated for 14 d with SA and heme were incubated for 30 min with the competitive NMDAR antagonist 50 μm APV. Total cell lysates were analyzed by immunoblotting to detect activated ERK1/2. The bottom shows the same blot reprobed with an antibody recognizing total ERK1/2. B, Cortical neurons treated for 14 d with SA and heme (H) were incubated for 30 min with SFK inhibitor PP2 (1 μm). Equal amounts of protein extracts were analyzed by Western blot with phospho-ERK1/2 antibody. The bottom shows the same blot reprobed with anti-total ERK1/2 antibody. C, Cortical neurons treated for 14 d with SA and heme were incubated for 30 min before harvesting with 10 μm ifenprodil (IFE) and with 1 μm PP2. Each column is the mean ± SD of phospho-ERK1/2/ERK1/2 ratio from three independent experiments. *p < 0.05. C, Control.