Thioredoxin-1 expression regulated by morphine in SH-SY5Y cells

► Morphine induced thioredoxin-1 expression. ► Morphine did not influence thioredoxin binding protein-2 expression. ► Naloxone inhibited the increased level of thioredoxin-1 caused by morphine. ► Morphine induced thioredoxin-1 expression through PI3K and ERK pathways.