INFLUENCE OF CALCIUM ON VASCULAR REACTIVITY IN PREGNANT RATS

Objective: The fundamental aim of the study was to test whether calciu m has some influence on vascular reactivity (VR) during pregnancy. Met hods: In three groups of pregnant Wistar rats, VR was studied in isola ted organs (aorta), using noradrenaline as a presser agent. The first group of rats was placed on a normal diet; the second, on a low-calciu m diet; and the third, on a high-calcium diet. The concentration of no radrenaline required to produce a determined contractile response in t he vessel was measured (effective concentration = EC(50)) with VR bein g deduced from that: the stronger the EC, the weaker the VR and vice v ersa. Results: In rats on a low-calcium diet the EC(50) was significan tly higher than in those on a normal diet and a high-calcium diet. Con clusions: In rats on a low-calcium diet VR increased significantly fro m the second week of gestation, compared to rats on normal or high-cal cium diet.