Jean-Pierre Changeux worked on the bacterial regulatory enzyme, l-threonine deaminase which led to the general discovery that chemical signals that regulate the biological activity of proteins act at “allosteric” sites distinct from the biologically active sites(1961)as a Ph.D. student in Jacques Monod Laboratory, and involved a cooperative conformational transition (Monod-Wyman-Changeux 1965) viewed as a general molecular mechanism of signal transduction. His subsequent career led to the chemical identification of eukaryotic acetylcholine nicotinic receptor, the first identified neurotransmitter/drug membrane receptor and ion channel together with the demonstration of its allosteric properties and of its structural homology with prokaryotic receptors. In addition to the novel concept of allosteric modulators that creates a revolution in the field of drug design, he has brought new perspectives on nicotine addiction, the higher function of the brain and their pathologies.