Jean Rossier MD, PhD is a neuropharmacologist. He has made several important contributions in neuroscience. Among then, 1) the discovery with Floyd Bloom and Roger Guillemin of multiple opioïd peptides delineating several distinct neuronal systems involved in pain and reward, 2) the observation that beta-carbolines and other inverse agonists of the Benzodiazepine-GABA receptors facilitate performance in learning and memory tasks which has led pharmaceutical companies into development of promnesic drugs, 3) the discovery of two new important post-translational modifications of proteins : polyglutamylation and polyglycylation of tubulins, 4) the discovery of the role played by interneurons in controlling cerebral blood flow shedding light on the physiological mechanisms involved in functional NMR brain imaging and 5) the invention of single cell RT-PCR after patch clamp, an unique method allowing to link physiological studies of single cells with their selected gene expression.