Pregnancy-Induced Hypertension is Associated with an Activation of Endothelial Cells

Objective: The study examined the effects of salt-induced hypertension on vascular contractile responses during pregnancy and the mechanisms of the effects.Methods: Aortic rings from pregnant Wistar rats, fed for 6 weeks on diets containing 0.3% (control) and 8.0% (test) sodium chloride were contracted by phenylephrine, 5-hydroxytryptamine, and potassium chloride, in the presence and absence of either endothelium or 10−6 M indomethacin. Contractile responses to calcium chloride were also assessed.Results: High salt intake increased the systolic blood pressure of the rats. Rings from the high-salt-fed rats showed enhanced reactivity to phenylephrine, but not to potassium chloride and 5-hydroxytryptamine. Indomethacin treatment decreased the contractions of rings from the test rats to phenylephrine, but did not significantly affect the responses of rings from the control rats. Removal of endothelium resulted in similar increase in the contractile responses of rings from both groups of rats to phenylephrine ...