Influence of Calcium on Vascular Reactivity in Pregnant Rats

Abstract

Objective: The fundamental aim of the study was to test whether calcium has some influence on vascular reactivity (VR) during pregnancy.

Methods: In three groups of pregnant Wistar rats, VR was studied in isolated organs (aorta), using noradrenaline as a pressor agent. The first group of rats was placed on a normal diet; the second, on a low-calcium diet; and the third, on a high-calcium diet. The concentration of noradrenaline required to produce a determined contractile response in the vessel was measured (effective concentration = EC₅₀) with VR being deduced from that: the stronger the EC, the weaker the VR and vice versa.

Results: In rats on a low-calcium diet the EC₅₀ was significantly higher than in those on a normal diet and a high-calcium diet.

Conclusions: In rats on a low-calcium diet VR increased significantly from the second week of gestation, compared to rats on normal or high-calcium diet.

Key Words:

• Calcium
• Hypertension
• Vascular reactivity