In his long scientific carrier, Robert F. Furchgott, researched tissue metabolism for many decades, working with various organ tissues. In 1980, the outcome of his experiment with acetylcholine, paved the way to the discovery of the compound involved in blood vessel dilatation. With this experiment, he demonstrated that acetylcholine only dilates a blood vessel when the endothelium (i.e., the tissue that constitutes the internal surface of blood vessels) is intact. When a lesion was present in this tissue, dilatation by acetylcholine was prevented. Therefore, Furchgott concluded that the endothelium cells should have a role in the regulation of blood cells dilatation, through the production of an unknown molecule that induced the relaxation of the vascular smooth muscle cells. He named this unidentified molecule endothelium-derived relaxing factor--EDRF. Another researcher, the pharmacologist Louis J. Ignarro, was one of the scientists that searched for the chemical identity of Furchgott's EDRF. After...