Figure 2.
Effects of calpain activation on NR2 subunits in neurons. Neurons were exposed to NMDA receptor agonist stimulation over a 0-30 min time course and subjected to Western blot analysis with an N-terminal antibody that recognizes NR2A, NR2B (both 170 kDa), and NR2C (135 kDa) subunits. A representative Western blot (A) demonstrates the decrease in full-length NR2A/2B (170 kDa) (p = 0.016 for 30 vs 0 min; n = 13) as well as the simultaneous increase in levels of a 115 kDa species (0 vs 30 min = 0.0044; n = 12). This blot was overexposed to show more clearly both the breakdown product and the decrease of full-length NR2A/2B. The increase in the LMW species was inhibited by inclusion of 100 μm MK-801 in the treatment conditions (p = 0.0135 MK-801 vs 30 min; n = 12) (C). Inclusion of 100 μm MK-801 in the treatment conditions also prevented the decrease of full-length NR2A/2B (MK-801 vs 30 min = 0.0004; n = 12). NR2 immunoreactivity was quantitated as a percentage of the MK-801 control condition.