Figure 4.

The protective effect of piracetam against the effects of psychostimulants and opioids on class I SIRT proteins. Human primary astrocytes were exposed to cocaine (1 µM), METH (10 µM) and morphine (5 µM) alone or in combination with piracetam (10 µM) for 24 h. Controls were maintained in drug-free medium (without drug exposure). Representative blots showing the expression of class I sirtuins (A) SIRT-1, (B) SIRT-2, and (C) SIRT-3. (D–F) Densitometric analyses of each protein level to its corresponding GAPDH loading control (fold-change from control). (G) Effects of psychostimulants and opioids on the expression and translocation of SIRT-1 in the cytoplasm and nucleus. SIRT-1 expression (green) and nuclear staining with DAPI (blue) were observed using confocal microscopy (magnification 100$\times$, scale bar 100 μm). (H) Quantification of SIRT-1 fluorescence intensity (CTCF). (I) Effect of psychostimulants and opioids on the expression pattern of SIRT-2 in the cytoplasm. SIRT-2 expression (green) and nuclear staining with DAPI (blue) were observed using confocal microscopy (magnification 100x, scale bar 100 μm). (J) Quantification of SIRT-2 fluorescence intensity (CTCF). Data are expressed as the means ± SD of three independent experiments. ***P < 0.001, **P < 0.01, *P < 0.05, NS—Nonsignificant. Coexposure of psychostimulant or opioid with piracetam compared to psychostimulant or opioid alone. The supplementary information includes all full-length blots.