The Endothelium-derived relaxing factor (EDRF) is a strong

vasodilator Vasodilation, also known as vasorelaxation, is the widening of blood vessels. It results from relaxation of smooth muscle cells within the vessel walls, in particular in the large veins, large arteries, and smaller arterioles. Blood vessel wal ...

produced by cardiac endothelial cells in response to stress signals such as high levels of ADP accumulation or hypoxia. Robert F. Furchgott is widely recognised for this discovery, even going so far as to be a co-recipient of the 1998

Nobel Prize in Medicine The Nobel Prize in Physiology or Medicine () is awarded yearly by the Nobel Assembly at the Karolinska Institute, Nobel Assembly at the Karolinska Institute for outstanding discoveries in physiology or medicine. The Nobel Prize is not a single ...

with his colleagues

Louis J. Ignarro Louis Joseph Ignarro (born May 31, 1941) is an American pharmacologist. For demonstrating the signaling properties of nitric oxide, he was co-recipient of the 1998 Nobel Prize in Physiology or Medicine with Robert F. Furchgott and Ferid Murad ...

and

Ferid Murad Ferid Murad (September 14, 1936 – September 4, 2023) was an American physician and pharmacologist, and a co-winner of the 1998 Nobel Prize in Physiology or Medicine. Early life Ferid Murad was born in Whiting, Indiana, on September 14, ...

Nitric oxide Nitric oxide (nitrogen oxide, nitrogen monooxide, or nitrogen monoxide) is a colorless gas with the formula . It is one of the principal oxides of nitrogen. Nitric oxide is a free radical: it has an unpaired electron, which is sometimes den ...

(NO) is a key component in any EDRF as these compounds either include NO or are structurally in the form of NO.

Physiological Functions and production

EDRF serves various functions, of which the most common and topical are vasodilation and the prevention of

platelet adhesion Platelets or thrombocytes () are a part of blood whose function (along with the coagulation#Coagulation factors, coagulation factors) is to react to bleeding from blood vessel injury by clumping to form a thrombus, blood clot. Platelets have no ...

. EDRF also plays a role in the production of

cyclic GMP Cyclic guanosine monophosphate (cGMP) is a cyclic nucleotide derived from guanosine triphosphate (GTP). cGMP acts as a second messenger much like cyclic AMP. Its most likely mechanism of action is activation of intracellular protein kinases in res ...

. EDRF is produced from

L-arginine Arginine is the amino acid with the formula (H2N)(HN)CN(H)(CH2)3CH(NH2)CO2H. The molecule features a guanidino group appended to a standard amino acid framework. At physiological pH, the carboxylic acid is deprotonated (−CO2−) and both the ...

by an enzyme (endothelial nitric oxide synthase) that is dependent on calcium-calmodulin and

NADPH Nicotinamide adenine dinucleotide phosphate, abbreviated NADP or, in older notation, TPN (triphosphopyridine nucleotide), is a cofactor used in anabolic reactions, such as the Calvin cycle and lipid and nucleic acid syntheses, which require N ...

- this occurs in the cardiac endothelium. EDRF then diffuses to the smooth muscle in vascular tissue (vessels may be large or small), here it enacts

endogenous Endogeny, in biology, refers to the property of originating or developing from within an organism, tissue, or cell. For example, ''endogenous substances'', and ''endogenous processes'' are those that originate within a living system (e.g. an ...

vasodilation. Moreover, it serves the function of preventing sympathetic vasoconstriction - when the sympathetic nervous system, reacting to a situation perceived as dangerous, attempts to raise blood pressure through vasoconstriction. The NO compound is also capable of reducing clotting in the blood stream due to its ability to prevent platelet adhesion and aggregation.

Related pathology

Atherosclerosis and hypertension are grave contributors in the group of pathological conditions under the umbrella of Cardiovascular disease. Among these conditions is also the disfunction of the endothelium, which given its properties of vasodilation when functional, can cause excessive vasoconstriction, thus leading back to hypertension. Another effect of this particular disfunction may also be excessive platelet adhesion, signifying a significant increase in blood clots, thus the promotion of a prothrombotic state.

References

External links

* * * Nitrogen compounds Nitrogen cycle Vasodilators {{biology-stub