Figure 3.

Melatonin regulates IR-induced endoplasmic reticulum (ER) stress signaling (p-eIF2α, ATF4, and CHOP) in the SH-SY5Y neuronal cells. The mRNA levels of (A) activation of eIF2α, (p-eIF2α); (B) ATF4, and (C) CHOP were measured by reverse transcription PCR. Data are expressed as mean ± standard error and each experiment included three repeats per conditions. * p < 0.05, ** p < 0.01 compared with non-stimulated control; ^φ p < 0.05 compared with insulin stimulated cells. Mel: melatonin pretreatment for 24 h before insulin stimulation; ASK1 inhibitor: NQDI-1 600 nM treatment for 2 h before sampling.