The second of three scientifically minded brothers from Chicago, Paul Fatt received his education in Biochemistry at University of California Berkeley on the G.I. Bill after serving with the US Army in World War II. As a young graduate student, he joined University College London's (UCL) Biophysics Research Unit (later the Biophysics Department) in the summer of 1948. He and Katz decided that they would 'have a go' at using intracellular microelectrodes to examine the endplate potential (EPP). It is no exaggeration to say that the decision opened up a new era in our understanding of synaptic transmission. Together they carried out the first analysis of the endplate potential using intracellular microelectrodes, an experimental tour de force. This was the first compelling demonstration that synaptic receptors were chemically gated ion channels.
During the spring of 1950, Fatt and Katz made the chance observation that, when examined on a high recording gain, the endplate region of skeletal muscle was the site of spontaneous ongoing electrical activity. This they ascribed to the discharge of multimolecular 'quanta' of acetylcholine (ACh) from the nerve terminal. In a series of elegant experiments, they demonstrated that these events, dubbed miniature endplate potentials (MEPPs), represented the 'basic coin' of chemical synaptic transmission and that the full-sized EPP triggered by a nerve impulse represented the superposition of a large number of synchronously occurring MEPPs. The EPP, and its constituent 'miniatures', became the fundamental model against which transmission at other chemical synapses, including those in the brain, have subsequently been compared.
