Illustrations Figure 1 The effects of magnesium on the long-term memory in NORT: Experiment 1 (A), Experiment 2 (B), and Experiment 3 (C). Vertical bars represent the time (mean value ± SEM) that animals spent in the exploration of the familiar (f.o.) and the novel object (n.o.), with lines connecting time values of a single animal. Data were analyzed using RM ANOVA to check for significant simple effects of the object preference factor. * (p<0.05); ** (p<0.01) and *** (p<0.001), relative to the familiar object exploration time, within each group. Figure 1 Tableaux

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Auteurs

1 Department of Physiology, Faculty of Pharmacy, University of Belgrade, VojvodeStepe 450, 11121 Belgrade, Serbia

2 Department of toxicology “Akademik Danilo Soldatović”, Faculty of Pharmacy, University of Belgrade

* Correspondence: Bojan Batinić, Department of Physiology, Faculty of Pharmacy, University of Belgrade, VojvodeStepe 450, 11121 Belgrade, Serbia.

Although a magnesium-mediated attenuation of memory deficits was reported in animal models of ageing and traumatic brain injury, a possible memory enhancement in healthy subjects has not been investigated yet. We used novel object recognition test (NORT) to examine the effects of acute (30 mg/kg) and chronic (50 mg/kg, 28 days) Mg-sulfate treatment on the long-term memory (LTM) in healthy adult male rats, and to test the sustainability of magnesium effects in the models of acute and chronic (21 days) ACTH administration (10 μg/animal), mimicking the stress- and depression-like conditions. A single dose of Mg-sulfate enhanced the LTM retrieval in the 24 h inter-trial NORT protocol, in healthy, as well as in rats acutely treated with ACTH. Memory enhancement was also detected after 4-week long Mg-sulfate intake, in both healthy and rats chronically treated with ACTH. While the present findings on procognitive effects of chronic Mg-sulfate treatment corroborate with those from studies on the therapeutic potential of Mg-threonate, the current study is the first to report on memory enhancement induced by a single dose of magnesium.