Template:Aquatic layer topics. An abyssal plain is an underwater plain on the deep ocean floor, usually found at depths between 3000 and 6000 m. Lying generally between the foot of a continental rise and a mid-ocean ridge, abyssal plains cover more than 50% of the Earth âs surface.
Murad discovered in 1977 that nitroglycerin and related artery-widening compounds act by releasing nitric oxide. Furchgott later concluded that cells in the inner lining of blood vessels secrete some unknown substance that makes vessels dilate.
The chemical, nitric oxide, signals blood vessels to open and close in response to the body's changing need for increased or decreased blood flow. Individuals with elevated cholesterol have an impaired ability to relax, or dilate, their blood vessels, which researchers attribute to a problem in nitric oxide activation. In individuals whose cholesterol levels were lowered by the drug fluvastatin, more nitric oxide was produced, improving dilation.