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Increase in nitric oxide bioavailability improves endothelial function in endothelin-1 transgenic mice
Thomas Quaschning1, Serkan Koçak, Christian Bauer
1Department of Medicine, Division of Nephrology, University Hospital of Würzburg, Würzburg, Germany.
Summary
Increased nitric oxide (NO) bioavailability counteracts endothelin-1 (ET-1) effects in transgenic mice, improving vascular function and preventing hypertension. This highlights NO
Area of Science:
- Cardiovascular Physiology
- Endocrinology
- Vascular Biology
Background:
- Endothelin-1 (ET-1) is a potent vasoconstrictor.
- Transgenic mice overexpressing ET-1 maintain normal blood pressure.
- Hypothesis: Increased nitric oxide (NO) bioavailability antagonizes vascular ET-1 effects.
Purpose of the Study:
- Investigate the interplay between ET-1 and NO in vascular function.
- Determine if enhanced NO bioavailability counteracts ET-1-induced vasoconstriction.
- Assess the impact on blood pressure regulation in ET-1 transgenic mice.
Main Methods:
- Assessed endothelium-dependent and -independent vascular function in isolated aortic rings.
- Utilized acetylcholine, sodium nitroprusside, ET-1, and big ET-1.
- Administered L-N(G)-nitroarginine methyl ester (L-NAME) to inhibit NO synthase.
- Measured urinary nitrate/nitrite excretion.
Main Results:
- Enhanced endothelium-dependent relaxation in ET-1 transgenic mice.
- L-NAME inhibited relaxation, confirming NO system involvement.
- Reduced vascular contraction to ET-1 and big ET-1 in transgenic mice.
- Elevated urinary nitrate/nitrite excretion in transgenic mice.
Conclusions:
- Increased NO bioavailability counteracts elevated ET-1 levels in transgenic mice.
- This counteraction improves endothelium-dependent relaxation and maintains normal vascular tone.
- Upregulation of NO production can prevent hypertension in the presence of an activated ET system.