Fig. 3. ATP synthesis and ADP/ATP ratio during apoptotic process. ATP production and ADP/ATP ratio were measured in sham control and treated cortical cultures after 9–10-hour exposures. (A) Cellular ATP level was markedly reduced by serum deprivation; pyruvate (5 mM) and succinate (20 mM) each enhanced the ATP production. n=6 measurements. (B) ADP/ATP ratio was decreased during serum deprivation, and was improved by co-applied pyruvate or succinate (n=6). (C) ATP level was reduced by 0.1 µM staurosporine; in contrast to the effect in A, pyruvate (5 mM) did not increase ATP levels: the ATP level was even lower in the presence of pyruvate. Nevertheless, succinate (20 mM) markedly enhanced the ATP level. n=8. (D) Staurosporine decreased the ADP/ATP ratio, which was improved by both pyruvate and succinate. n=8. *P<0.05 compared with controls; #P<0.05 compared with serum deprivation or staurosporine alone.