What are the biological effects of neuropeptides and other neuroactive substances? What are their receptors, their pharmaceutical applications? The intensive search for answers to these questions culminated in the 2000 Nobel Prize for Medicine/Physiology being awarded to A. Carlsson, P.Greengard, and E. Kandel for their pioneering research in signal transduction in the nervous system.This handbook gives a short but detailed overview of neuroactive substances, covering all neurotransmitters and most neuromodulators. It provides clear and comprehensive information on their biosynthesis and degradation, localization, receptors, signal transduction pathways, and biological effects in the central nervous system. Introductory chapters on general aspects and on methods for analyzing neuroactive substances make this a valuable tool for researchers, teachers, and advanced students in molecular biology, biochemistry, medicine, neurosciences, pharmacology, and physiology.