NPY reduces the activation of the Akt/FoxO3a axis triggered by oxidative stress under glutamate and tunicamycin in SH-SY5Y cell cultures. Western immunoblot analysis and densitometric quantification of AKT phosphorylation (Ser473) (A,B) with glutamate and tunicamycin (C,D) treatments at 12 h reveal a significant increase in AKT activation with glutamate/tunicamycin compared to the control group (F(1,16) = 69.66 in Figure (B) and F(1,16)= 12.93 in Figure (D), **** p < 0.0001, n = 3) and NPY treatment significantly decreases this activation (F(3,16) = 15.36, ** p < 0.01, **** p < 0.0001 represents significance between control and NPY group (blue), **** p < 0.0001 represents significance between glutamate and glutamate + NPY in Figure (B) (red), n = 3; F(3,16) = 44.88, *** p < 0.001, **** p < 0.0001 represents significance between control and NPY group (green), **** p < 0.0001 represents significance between tunicamycin and tunicamycin + NPY in Figure (D) (purple), n = 3). Western immunoblot analysis and densitometric quantification of FoxO3a phosphorylation (Ser 253) (E,F) with glutamate and tunicamycin (G,H) treatment at 12 h reveal a significant increase in FoxO3a activation with glutamate/tunicamycin compared to the control group (F(1,16) = 550.6 in Figure (F) and F(1,16)= 577.2 in Figure (H), **** p < 0.0001, n = 3) and NPY treatment significantly decreases this activation (F(3,16) = 12.99, *** p < 0.001 represents significance between control and NPY group (blue), **** p < 0.0001 represents significance between glutamate and glutamate + NPY in Figure (F) (red), n = 3; F(3,16) = 26.45, ** p < 0.01 represents significance between control and NPY group (green), **** p < 0.0001 represents significance between tunicamycin and tunicamycin + NPY in Figure (H) (purple), n = 3). Each band intensity of phospho-FOXO3a was normalized to the respective band intensity of β-actin. (I) Immunofluorescence images (representative) of treated SH-SY5Y cells showing the expression of phosphorylated FoxO3a. After 12 h of treatment, cells were fixed and immunostained with anti-phospho-FoxO3a (Ser253) antibody (red). Nuclei were stained with DAPI (blue). Scale bar = 10 μm.