Nicotine-induced memory impairment by increasing brain oxidative stress

Male Wistar rats were subjected to chronic nicotine treatment (0.3 mg/kg; 7 continuous days) and their memory performance was studied by means of Y-maze and multi-trial passive avoidance tasks. Nicotine significantly decreased spontaneous alternation in Y-maze task and step-through-latency in the multi-trial passive avoidance task, suggesting effects on both short-term memory and long-term memory, respectively. In addition, nicotine induced neuronal apoptosis, DNA fragmentation, reduced antioxidant enzymes activity, and increased production of lipid peroxidation and reactive oxygen species, suggesting pro-oxidant activity. Our results provide further support that nicotine-induced memory impairment is due to an increase in brain oxidative stress in rats.