Endothelium-derived relaxing factor (EDRF) is a bioactive molecule produced by the endothelial cells lining the blood vessels. It is primarily known for its vital role in regulating vascular tone and promoting vasodilation, which in turn helps maintain normal blood pressure and blood flow.
Originally identified as a compound released from endothelial cells, EDRF was later discovered to be nitric oxide (NO), a small molecule gas. Nitric oxide is synthesized and released by the endothelium in response to various physiological and chemical signals. It diffuses into the underlying smooth muscle cells of the blood vessel walls and acts as a signaling molecule.
EDRF/NO exerts its vasodilatory effects by relaxing the smooth muscles of the blood vessel walls, leading to their dilation and subsequent increase in blood flow. It achieves this by activating guanylate cyclase in smooth muscle cells, which increases the production of cyclic guanosine monophosphate (cGMP). Increased levels of cGMP then promote relaxation and prevent excessive constriction of blood vessels.
Moreover, EDRF/NO also possesses other beneficial properties, including anti-inflammatory and anti-platelet effects. It inhibits the adhesion of white blood cells to the endothelium, thus reducing inflammation. Additionally, NO inhibits platelet aggregation, preventing the formation of blood clots.
In summary, endothelium-derived relaxing factor (EDRF) refers to the bioactive molecule nitric oxide (NO) produced by endothelial cells. Its primary function is to regulate vascular tone by inducing vasodilation, ensuring normal blood pressure and blood flow. Furthermore, EDRF/NO possesses anti-inflammatory and anti-platelet properties, contributing to overall cardiovascular health.
