EXPOSURE OF PIGLET CORONARY ARTERIAL MUSCLE-CELLS TO LOW CONCENTRATIONS OF MG2-HEART-DISEASE PATIENTS RESULT IN RAPID ELEVATION OF CYTOSOLIC CA2+ - RELEVANCE TO SUDDEN-INFANT-DEATH-SYNDROME( FOUND IN BLOOD OF ISCHEMIC)

Exposure of cultured piglet primary neonatal coronary arterial smooth muscle cells to concentrations of ionized Mg2+ ([Mg2+](0) (i.e., 0.48, 0.3, 0.15 mM) found in blood of patients presenting with ischemic hea rt disease and in hypoxic neonates resulted in concentration-dependent elevation in intracellular free Ca2+ ions ([Ca2+](i); the lower the [ Mg2+](0), the higher the [Ca2+](i) rise. The lowest concentration of [ Mg2+], tested, i.e., 0.15 mM, resulted in a clear rounding-up (i.e., c ontraction) of many of the coronary smooth muscle cells; reintroductio n of normal 1.2 mM [Mg2+](0) failed to restore either normal [Ca2+](i) or cell shape. (C) 1997 Elsevier Science B.V.