title: Calcium regulation of spontaneous and asynchronous neurotransmitter release.
abstract: The molecular machinery underlying action potential-evoked, synchronous neurotransmitter release, has been intensely studied. It was presumed that two other forms of exocytosis, delayed (asynchronous) and spontaneous transmission, were mediated by the same voltage-activated Ca(2+) channels (VACCs), intracellular Ca(2+) sensors and vesicle pools. However, a recent explosion in the study of spontaneous and asynchronous release has shown these presumptions to be incorrect. Furthermore, the finding that different forms of synaptic transmission may mediate distinct physiological functions emphasizes the importance of identifying the mechanisms by which Ca(2+) regulates spontaneous and asynchronous release. In this article, we will briefly summarize new and published data on the role of Ca(2+) in regulating spontaneous and asynchronous release at a number of different synapses. We will discuss how an increase of extracellular [Ca(2+)] increases spontaneous and asynchronous release, show that VACCs are involved at only some synapses, and identify regulatory roles for other ion channels and G protein-coupled receptors. In particular, we will focus on two novel pathways that play important roles in the regulation of non-synchronous release at two exemplary synapses: one modulated by the Ca(2+)-sensing receptor and the other by transient receptor potential cation channel sub-family V member 1.
authors: Division of Pulmonary & Critical Care Medicine, Oregon Health & Science University, Portland, OR 97239, United States. smisteph@ohsu.edu
authors: Stephen M
authors: SM
authors: Smith
authors: Wenyan
authors: W
authors: Chen
authors: Nicholas P
authors: NP
authors: Vyleta
authors: Courtney
authors: C
authors: Williams
authors: Chia-Hsueh
authors: CH
authors: Lee
authors: Cecilia
authors: C
authors: Phillips
authors: Michael C
authors: MC
authors: Andresen
mesh_terms: D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000378:metabolism; D005089:Exocytosis / Q000502:physiology; D018698:Glutamic Acid / Q000378:metabolism; D006801:Humans; D008274:Magnesium / Q000378:metabolism; D018377:Neurotransmitter Agents / Q000378:metabolism*; D043562:Receptors, G-Protein-Coupled / Q000378:metabolism; D013569:Synapses / Q000378:metabolism; D009435:Synaptic Transmission / Q000502:physiology; D013572:Synaptic Vesicles / Q000378:metabolism; D050916:TRPV Cation Channels / Q000378:metabolism
chemical_list: D015220:Calcium Channels; D018377:Neurotransmitter Agents; D043562:Receptors, G-Protein-Coupled; D050916:TRPV Cation Channels; C494482:TRPV1 protein, human; D018698:Glutamic Acid; D008274:Magnesium; D002118:Calcium