Glutamate and ATP at the Interface of Metabolism and Signaling in the Brain, 1

ATP was selected very early as the main source of biological energy, and thus became an indispensable feature of life on Earth. This was a critical evolutionary choice because it shaped enzymatic systems to utilize ATP in energy-dependent reactions and necessitated appearance of the universal intracellular signaling system based on calcium ions as keeping cytosolic Ca 2+ extremely low became vitally important, since otherwise insoluble Ca 2+ -phosphates would preclude the cell energetics. Thus all living cells on the Earth beginning from the most primitive ones had high cytosolic concentrations of ATP and this is little surprise that ATP was soon utilized by nature for another fundamental function of sending information from one living cell to another. In summary ATP acts as main energy source and is pivotal for numerous signaling cascades both inside the cells (by fuelling various transport systems and donating phosphate groups) and between the cells (by chemical transmission). Similarly glutamate acts as an important molecule for both intercellular signaling though glutamatergic transmission and cell energetics by contributing to ATP production.§In this collection of chapters, written by the leading experts in the field of cell metabolism and energetics, intracellular signaling and neurotransmission we covered various aspects of the interfacing between these two fundamental molecules. This book will be particularly useful for researchers, students, physicians and psychotherapists working in the field of neurobiology, neurology and psychiatry.