Effects of magnesium deficiency on dermal mast cells in rats

The effects of dietary magnesium (Mg) deficiency on dermal mast cells were studied in young Wistar rats weighing about 50 g. The rats fed with a Mg-deficient diet (0.001% Mg) showed hyperemia on the 3rd or the 4th day after they were fed the diet. The dermal mast cells of the control rats were filled with granules, while the cells of rats fed the Mg-deficient diet for 4 days contained less granules than the controls, but contained extensively dilated rough surfaced endoplasmic reticulum, well-developed Golgi complexes, many mitochondria and ribosomes. These data suggest that hypomagnesemia could induce a release of histamine from dermal mast cells. So, the effect of a low Mg medium on the release of histamine was studied using peritoneal mast cells in vitro. A low Mg medium (0.2 mM Mg) induced much more histamine release than control medium (1 mM Mg) from the peritoneal mast cells obtained from both control and Mg-deficient rats fed with the Mg-deficient diet for 2 days. The peritoneal mast cells obtained on the 8th day of Mgdeficiency released much more histamine than controls in 1 mM Mg medium. These results suggest that hyperemia observed in Mg-deficient rats depends partly on histamine released from dermal mast cells.