Endogenous and exogenous nitrates.
The endothelium-derived relaxing factor (EDRF) is nitric oxide (NO) or a closely related nitrosothiol derivative. It is formed from the amino acid, L-arginine. NO is rapidly inactivated locally and is instantly destroyed by haemoglobin when released into the blood stream. EDRF-NO as well as NO generated from vasodilator nitrates act by activation of soluble guanylate cyclase, elevating cellular cyclic GMP levels, causing vasodilatation and inhibition of platelet aggregation. Endothelium-dependent vasodilatation is attenuated in hypertension, atherosclerosis and diabetes. This is due to either loss of endothelium or deficient formation of EDRF-NO. In these conditions, therapy with exogenous nitrates may substitute for a failing endogenous mechanism.
Anggård
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William Harvey Research Institute, St. Bartholomew's Hospital Medical College, London, UK.
D006801:Humans; D009566:Nitrates / Q000627:therapeutic use; D009569:Nitric Oxide / Q000502:physiology*
D009566:Nitrates; D009569:Nitric Oxide