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Negative feedback regulation of endothelial cell function by nitric oxide
G M Buga1, J M Griscavage, N E Rogers
1Department of Pharmacology, University of California, School of Medicine, Los Angeles.
Circulation Research
|November 1, 1993
Summary
Nitric oxide (NO) inhibits its own production by acting as a negative feedback modulator of endothelial NO synthase. This finding reveals a key regulatory mechanism in vascular endothelial cell function.
Area of Science:
- Biochemistry
- Physiology
- Vascular Biology
Background:
- Nitric oxide (NO) is a critical signaling molecule in vascular endothelium.
- Previous research indicated NO's inhibitory effect on neuronal NO synthase.
- The role of NO in modulating endothelial NO synthase (eNOS) activity remained unclear.
Purpose of the Study:
- To investigate if nitric oxide (NO) acts as a negative feedback regulator of endothelial cell function.
- To determine if NO inhibits NO synthase in vascular endothelial cells.
Main Methods:
- Studied NO synthase inhibition by NO and NO-donor agents in bovine aortic endothelial cells.
- Utilized oxyhemoglobin to block NO's inhibitory effects.
- Assessed NO biosynthesis in intact endothelial cells and arterial rings under various stimuli.
Main Results:
- NO and NO-donor agents noncompetitively inhibited endothelial NO synthase.
- Oxyhemoglobin reversed NO's inhibition and increased NO synthase activity.
- Pretreatment with NO donors reduced NO production in response to bradykinin and shear stress.
- NO donors diminished endothelium-dependent arterial relaxation.
Conclusions:
- Nitric oxide (NO) functions as a negative feedback modulator of endothelial NO synthase.
- This regulatory role impacts overall vascular endothelial cell function.
- Findings highlight a novel mechanism controlling NO bioavailability in the vasculature.