A thin layer of cells lining the interior surface of blood vessels and lymphatic vessels is called endothelium. Endothelial cells perform many functions such as barrier function, blot clot formation, formation of new blood vessels and blood pressure regulation through vasoconstriction and vasodilation. The contraction of the muscular wall of the blood vessels results in narrowing of blood vessels which is called vasoconstriction. It plays a key role to stop internal bleeding and heavy loss of blood. The constriction of blood vessels restricts the blood flow and thus results in retention of body heat. The process of vasoconstriction is essential to maintain mean arterial pressure. The top open access journals are peer reviewed scholarly journals of Journal of Autacoids & Hormones. The top open access journals are freely available on the public internet domain, allowing any end users to read, download, copy, distribute, prink, search or link to the full texts of the articles. These provide high quality, meticulously reviewed and rapid publication, to cater the insistent need of scientific community.