Figure 3. Sirt3 activity is downregulated by Aβ-42 in vitro. Primary cortical neurons were treated with Aβ-42 (0, 10,100,1000 ng/ ml) for 24 hours. (A) NAD+/ NADH ratio; (B) Mitochondrial Sirt3 deacetylation activity (the ratio of fluorescent intensity to total protein); (C) ATP levels were decreased when Aβ-42 concentration was increased. (D) The correlation between Sirt3 protein levels and its deacetylation activity. n=6 per group, * p< 0.05, **p< 0.01.