Chapter 7 - Release of Neurotransmitters

Abstract

This chapter summarizes classical knowledge and recent advances in the release of neurotransmitters, emphasizing evidence supporting present concepts, rather than a recitation of dogma. Topics covered include: • Structural organization of chemical synapses • Quantal nature of transmission; identification of the synaptic vesicle as the physical quantum • Vesicle membrane and transmitter cycles • Biophysics of excitation-secretion coupling; secretory trigger properties • Calcium microdomains in triggering exocytosis • Mobilizing vesicles to docking sites and priming vesicles for release • Presynaptic protein identification by vesicle purification and genetics • SNARE proteins: assembly, disassembly, and vesicle fusion • Synaptotagmin: calcium sensor and secretory trigger • Docking and priming proteins • Molecular mechanisms of endocytosis and vesicle refilling • Quantal analysis at neuromuscular junctions and central synapses • Poisson and binomial models; meaning of statistical parameters • Limitations of the standard Katz model • Single and multivesicular release at active zones • Spontaneous vs. evoked release • Estimating and manipulating statistical parameters • Quantal analysis of release modulation