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 organic nitrates, including nitroglycerin, isosorbide dinitrate and isosorbide mononitrate, act as prodrugs for nitric oxide (NO) which is a potent vasodilator gas. Nitric oxide activates guanylyl-cyclase in vascular endothelial cells, which increases intracellular cyclic GMP and thereby reduces intracellular calcium concentrates and dephosphorylates myosin light chains causing relaxation of smooth muscle cells.