Table 1. Digestion of NMDA-R associated proteins following activation of resident calpain-1.
| Stimuli | HSP90 | NR2B | 160 kD nNOS | 130 kD nNOS |
|---|---|---|---|---|
| Vehicle | 100 ± 7 | 100 ± 8 | 83 ± 8 | 18 ± 6 |
| NMDA (500 μM) | 85 ± 7 | 56 ± 7 | 44 ± 7 | 52 ± 6 |
| NMDA (500 μM) + CI-1 (1 μM) | 100 ± 8 | 103 ± 5 | 93 ± 7 | 10 ± 5 |
| Ca2+-ionophore (1 μM) | 75 ± 7 | 49 ± 7 | 38 ± 9 | 46 ± 7 |
| Ca2+-ionophore (1 μM) + CI-1 (1 μM) | 105 ± 5 | 106 ± 9 | 102 ± 7 | 8 ± 6 |
SK-N-BE cells were exposed to the indicated stimuli for 30 min at 37°C. The deoxycholate-soluble cell fraction was prepared as described in Methods and submitted to immunoprecipitation using anti-NR1 antibody. The immunoprecipitated material was analyzed by immunoblotting for the indicated proteins. The data shown are the quantification of the immunoreactive signals expressed as arbitrary units (means ± SD of five different experiments).