Effect of Magnesium Oxide Nanoparticles on Atropine-Induced Memory Impairment in Adult Male Mice

Abstract

Background: Previous studies have shown that magnesium oxide nanoparticles (MgO-n) improve passive avoidance memory in adult male mice. Alternatively, muscarinic receptors of the cholinergic system have a primary role in memory formation but their relationship with the improvement effects of magnesium on memory is not clear. Objectives: The aim of this study was to investigate the effect of nano magnesium oxide on memory deficits induced by atropine as a muscarinic receptor antagonist in passive avoidance memory tests. Materials and Methods: In this experimental study, NMRI male mice were placed in groups receiving atropine (0.1 and 1 mg/kg), recipient of MgO-n (1, 2.5, and 5 mg/kg) and groups receiving atropine in effective dose and different doses of MgO-n were used. Saline was used as a vehicle for drugs in the control groups. Memory was evaluated with a step-down apparatus to determine the coming down latency from a safe platform on days 1, 3, and 7 after training. Locomotor activity was also evaluated through an open field test in all groups after memory measurements. Results: The results showed that atropine (1 mg/kg) decreased the latency time of coming down from the podium and induced memory deficits (P < 0.01). MgO-n in doses of 2.5 and 5 mg/kg caused a significant increase in latency time of coming down from the podium over one week (P < 0.001). MgO-n was able to reverse memory impairments resulting from atropine (1 mg/kg) (P < 0.001). Locomotor activity did not change in any of the groups. Conclusions: It seems that the potentiating effect of MgO-n on memory is due to interference with the cholinergic pathway.