A single dose of magnesium, as well as chronic administration, enhances long-term memory in novel object recognition test, in healthy and ACTH-treated rats

: 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.