FIGURE 8.

NR2B-containing NMDARs mediate both p38 MAPK activation in mature neuron and ERK1/2 activation in immature neuron. At 3 or 12DIV, neurons were starved for 6 h in DMEM without any supplement and were pretreated with MK-801 (0.3 μm), Ro-256981 (Ro25, 0.5 μm), NVP-AMM077 (NVP, 0.5 μm), or PBS for 20 min followed by treatment with or without NMDA (100 μm) for 15 min, and whole lysates were harvested. Immunoblotting was done by using of anti-phosphorylated p38 or ERK1/2 antibodies (p-p38, p-ERK1/2) and anti-total p38 or ERK1/2 (t-p38, t-ERK1/2) antibodies, with the latter serving as an internal control for protein loading to assess the activation level of p38 and ERK1/2. A and B, representative blots from three independent experiments. C and D, scanning densitometry was quantified and normalized to control (Con) on the same Western blots. *, p < 0.05; ***, p < 0.001 versus control; #, p < 0.05; ###, p < 0.001 versus NMDA + PBS. Note that NMDA induced ERK1/2 activation in 3DIV neurons, and p38 activation in 12DIV neurons was significantly decreased in the presence of Ro-6981 and that the NMDA-induced weak ERK1/2 activation in 12DIV was increased in the presence of Ro-6981 but decreased in the presence of NVP-AMM077.