Decreased cytosolic free calcium concentration in lymphocytes of magnesium-supplemented DOCA-salt hypertensive rats.

The effect of magnesium supplementation on blood pressure and lymphocyte cytosolic free calcium concentration (L-[Ca2+]i; nM) was examined in DOCA salt hypertensive rats (DSR). Magnesium was administered for 4 weeks with a standard diet in the form of 1% MgO (850 mg magnesium/100 g). In magnesium-supplemented DSR (DS-Mg), the elevation of systolic blood pressure (SBP; mmHg) was significantly attenuated (136.7 +/- 23.0 vs 180.6 +/- 23.4, p less than 0.005) and the L-[Ca2+]i was significantly lower (70.5 +/- 7.0 vs 84.5 +/- 7.1, p less than 0.005) than in DSR which were fed the standard rat diet. Lymphocyte magnesium content (nEq/mg protein) in DSR was lower than in control rats (160.6 +/- 18.3 vs 182.3 +/- 13.9, p less than 0.05) and approximately the same as in DS-Mg (164.9 +/- 6.9, p less than 0.05 vs control). Plasma magnesium concentration was slightly higher in DS-Mg than DSR (2.53 +/- 0.35 vs 2.21 +/- 0.26). We observed a significant positive correlation between SBP and L-[Ca2+]i in DS-Mg and in DSR as a whole. These findings suggest that oral magnesium supplementation can attenuate the elevation of blood pressure and simultaneously decrease the cytosolic free calcium concentration in DOCA salt hypertensive rats.