Magnesium ion content in vascular smooth muscle cells from spontaneously hypertensive and normotensive rats measured by electron-probe X-ray microanalysis

Whereas in blood cells decreased magnesium concentrations in essential hypertension have often been described, only sparse data exist on cellular magnesium content in vascular smooth muscle cells. Therefore, in aortic smooth muscle cells from 7 spontaneously hypertensive rats (SHR) of the Munster strain and 7 normotensive Wistar-Kyoto rats (WKY), the intracellular magnesium content was measured by electron-probe X-ray microanalysis. Measurements were performed in aortic cryosections 3 mu m thick. The magnesium ion content was 0.93+/-0.17 g/kg dry weight in SHR versus 1.14+/-0.12 g/kg dry weight in WKY (p < 0.05). In conclusion, aortic smooth muscle cells from SHR are characterized by a markedly lowered intracellular magnesium ion content as compared with normotensive cells. The results may be due to genetically determined disturbances in transmembrane magnesium ion transport, Cellular magnesium handling may be disturbed in SHR aortic smooth muscle as it is in hypertensive blood cells.