Fig. 6.

Caspase 9 and 3 are activated relatively late after exposure to DTDP. Neuronal cultures exposed to 100 μm DTDP for 10 min and then washed and harvested at various time points to assess the extent of caspase cleavage using fluorometric peptide substrates. Lysed cells were incubated in the presence of either the fluorogenic caspase 9 substrate (LEHD-AFC) or the caspase-3 substrate (DEVD-AFC). Activity was then calculated as fluorescent units per microgram of protein and expressed as activity in relative units compared with control. Data represent the average ± SEM of at least six experiments performed in duplicate.p < 0.05; one-way ANOVA.