Introduction. Endothelium-derived relaxing factor (EDRF) is an endogenous vasodilator that endothelial cells produce and subsequently release in response to various changes in normal physiologic as well as pathophysiologic changes.

What is endothelium-dependent hyperpolarization?

Endothelium-dependent hyperpolarizing factor (EDHF) is a powerful vasodilator influence in small resistance arteries and thus an important modulator of blood pressure and flow. As the name suggests, EDHF was thought to describe a diffusible factor stimulating smooth muscle hyperpolarization (and thus vasodilatation).

How does the endothelium affect blood pressure?

In summary, due to its position between the blood pressure and smooth muscle cells responsible for peripheral resistance, the endothelium is thought to be both victim and offender in arterial hypertension. The delicate balance of endothelium-derived factors is disturbed in hypertension.

Is called EDRF responsible vasodilation *?

We provide evidence that EDRF mediates the vasodilator response to acetylcholine and histamine in resistance blood vessels in perfused rat kidney and mesentery. The possibility that EDRF has a physiological role to play in regulating the calibre of resistance blood vessels is discussed.

What is the role of the endothelium?

The endothelium is a thin membrane that lines the inside of the heart and blood vessels. Endothelial cells release substances that control vascular relaxation and contraction as well as enzymes that control blood clotting, immune function and platelet (a colorless substance in the blood) adhesion.

How does hyperpolarization lead to relaxation?

Stimulation of the endothelial lining of arteries with acetylcholine results in the release of a diffusible substance that relaxes and hyperpolarizes the underlying smooth muscle. Nitric oxide (NO) has been a candidate for this substance, termed endothelium-derived relaxing factor.

What happens when endothelium is activated?

The five core changes of endothelial cell activation are loss of vascular integrity; expression of leucocyte adhesion molecules; change in phenotype from antithrombotic to prothrombotic; cytokine production; and upregulation of HLA molecules.

Why study endothelium-dependent vasodilation?

Therefore, the study of endothelium-dependent vasodilation mechanisms has commanded the investigations in the field of endothelial function. Even today, the term endothelial dysfunction is frequently assumed to mean loss of endothelium-dependent vasodilation, regardless of the several other functions of these cells [1].

What is endothelial dysfunction and how is it defined?

Even today, the term endothelial dysfunction is frequently assumed to mean loss of endothelium-dependent vasodilation, regardless of the several other functions of these cells [ 1 ].

Is hydhydrogen sulfide an endothelium-associated dilator?

Hydrogen sulfide is a novel gaseous endothelium-derived vasodilator. Together, these mechanisms compose an integrative platform providing an endothelium-associated dilator tone. Studies from our laboratory described in the present chapter were supported by grants from Fapesp, CNPq, Finep/Pronex e Fundação EJ Zerbini.

What is the role of nitric oxide in the pathophysiology of vasodilation?

Vasodilation is the archetypal function of the endothelial cell and the discovery of paracrine-dependent vasorelaxation by endothelium-derived production of the gaseous mediator nitric oxide (NO) was revolutionary. NO mediates its regulatory vasorelaxing effects through guanilyl cyclase activation.