The acetylcholine nicotinic receptor is an ionic channel whose aperture is directly controlled by acetylcholine. It is a key molecule in the chemical communication between nerve cells and between nerve cell and muscle. The structure and function of muscular nicotinic receptors have been unraveled in recent years and its beauty and mysteries were reviewed in the Santorini NATO ARW organized by Dr. Maelicke in 1986. The neat, linear structure of this molecule and its conservation throughout evolution, from bacteria to humans, have led to the suggestion that it has reached the optimal structure...