Article
Influence of HDL on blood pressure regulation
Einfluss von HDL auf die Blutdruckregulation
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Published: | November 11, 2004 |
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High-density lipoproteins (HDL) are a major atheroprotecitve factor, and plasma HDL-cholesterol levels are inversely proportional to the incidence of cardiovasular disease. However, the mechanisms by which HDL exerts its powerful atheroprotective effect are still not entirely clear. In this study we investigated whether HDL has direct influence on blood pressure in Wistar rats and in mice.
Influence of HDL on mean arterial blood pressure was measured in Wistar rats using intraarterial blood pressure measurement. Next influence of HDL in phenylephrine precontracted thoracic arteries of Wistar rats was measured using a wire myograph. The same experiments were redone in knockoutmice for endothelial nitric-oxide synthases (eNOS -/-).
Intraarterial application of 1mg HDL did not affect mean-arterial blood pressure (MAP) in Wistar rats. Permanent application of endothelin (1000 ng/h per 300 g rats) increased MAP by 19.7 ±2.1 mmHg. Application of 1mg HDL to endothelin induced vasoconstriction in rats induced a significant(p<0.05) reduction of MAP by 9.9±2.1 mmHg. In phenylephrine preconstricted aortae of Wistar rats, HDL induced a dose dependent vasodilation with a maximum at 0.5mg/ml HDL. After denudation of endothelium, HDL could not induce any vasodilation. In eNOS -/- mice HDL could not exert any vasodilation in PE-preconstricted arteries with intact endothelium.
We conclude that HDL can directly affect blood pressure. This effect is endothelium-dependent. We could demonstrate that HDL induces changes in blood pressure via activation of eNOS.