Stability of brain content of magnesium in experimental hypomagnesemia

Magnesium is important in cerebral function. If there is a deficiency and neurological symptoms accrue, we hypothesised that Mg 2+ deficiency causes neurological symptoms by decreasing the level of Mg 2+ in cerebral tissue. The content of magnesium was determined in 12 brain structures in magnesium-deficient rats. Experiments were carried out for 40 days in two groups of Wistar male rats made magnesium-deficient (MD) by a well-controlled diet (50 mg of Mg 2+/kg of food), and a control group (CG) rats fed normal diet (1 g of Mg 2+/kg of food). At the end of the 40 days, the clinical signs of hypomagnesemia were sought in the MD rats and Mg 2+ concentration levels were measured in the blood and brain. The results showed variable distribution of Mg 2+ in the different brain structures, both in CG and MD rats; in the MD rats there is an important stability of global Mg 2+ content of the brain. Although the global values for Mg 2+ in the brain did not decline in MD rats, there was a significant decrease in Mg 2+ in the brainstem. We conclude that the brain is able to maintain a stable concentration of Mg 2+ during chronic hypomagnesemia, but its topographic variations could account for some of neurological signs accompanying this condition.