MICE SELECTED FOR LOW AND HIGH BLOOD MAGNESIUM LEVELS - A NEW MODEL FOR STRESS STUDIES

Extra- and intracellular magnesium levels have previously been shown t o be genetically controlled in humans and in the mouse. To further stu dy this genetic regulation, mice were selected from; a heterogeneous p opulation, for low (MGL mice) and high (MGH mice) red blood cell (RBC) magnesium values. These values diverged rapidly in the two strains, t o reach a stable difference between the 14th and 18th generations. MGL mice also exhibited significantly lower plasma, kidney, and skull bon e magnesium contents and higher urinary magnesium excretion and total brain weights. Moreover, in stressful conditions, MGL mice displayed a more aggressive behavior that the control MGH strain. Altogether, MGL mice showed a more restless behavior, a higher rectal temperature, an d much higher brain (+17%) and urine (+200%) noradrenaline levels than the MGH animals. These strains, thus, constitute a new animal model f ar the study of magnesium metabolism and its relationships with catech olamines, stress sensitivity, and aggressive behavior. (C) 1997 Elsevi er Science Inc.