Fig. 2.

Cytoprotective effects of SNAP and caspase inhibitors on survival of PC12 cells in serum-free media. Cells were treated with SNAP (100 μm), Ac-YVAD-cho (200 μm), or Ac-DEVD-cho (200 μm) in serum-free media. At 24 hr, cell viability was determined by counting intact nuclei (mean ± SD; n = 4). PC12 cells were collected, washed with ice-cold PBS, and lysed in 100 mmHEPES buffer, pH 7.4, containing protease inhibitors. The cytosolic fraction was obtained by centrifugation at 100,000 ×g for 30 min at 4°C. Caspase enzyme activity was measured with Ac-YVAD-pNA for caspase-1-like activity (or YVADase) and Ac-DEVD-pNA for caspase-3-like activity (or DEVDase) in a colorimetric assay (mean ± SD; n = 3). *p < 0.01 versus nonpretreatment.