Systemic administration of GBR12909 to increase endogenous DA significantly decreased both sIPSCs and mIPSCs; the effects were reversed by systemic prior administration of the GSK-3β inhibitor TDZD. A, Representative traces of the sIPSCs (left panel) and mIPSCs (right panel). B, Left panel, GBR12909 (10 mg/kg, i.p.) significantly decreased both frequency (p < 0.05) and amplitude (p < 0.01) of sIPSCs; these effects were completely blocked by TDZD (1 mg/kg, i.p.). Right panel, both frequency (p < 0.05) and amplitude (p < 0.01) of mIPSCs were significantly decreased by GBR12909 but only the amplitude was significantly prevented by TDZD.