Research Article

N-Methyl-N-Nitrosourea-Induced Photoreceptor Degeneration Is Inhibited by Nicotinamide via the Blockade of Upstream Events before the Phosphorylation of Signalling Proteins

Figure 4

Effect of NAM on cellular stress-related proteins. Representative western blots of ERK (a), Akt (b), and CREB (c) are indicated in each densitometry analysis graph. Increased phosphorylated forms of pERK1, pERK2, and pAKT were observed at Day 1 after MNU administration. Thereafter, pCREB was also upregulated. Data are shown as mean ± standard deviation (n = 4, , , and : p < 0.05, 0.01, and 0.001, Tukey’s multiple comparison test). CREB: cAMP response element binding protein; ERK: extracellular signal-regulated kinase; MNU: N-methyl-N-nitrosourea; and NAM: nicotinamide.