%0 Journal Article
%A Valérie De Crescenzo
%A Ronghua ZhuGe
%A Cristina Velázquez-Marrero
%A Lawrence M. Lifshitz
%A Edward Custer
%A Jeffrey Carmichael
%A F. Anthony Lai
%A Richard A. Tuft
%A Kevin E. Fogarty
%A José R. Lemos
%A John V. Walsh, Jr
%T Ca2+ Syntillas, Miniature Ca2+ Release Events in Terminals of Hypothalamic Neurons, Are Increased in Frequency by Depolarization in the Absence of Ca2+ Influx
%D 2004
%R 10.1523/JNEUROSCI.4286-03.2004
%J The Journal of Neuroscience
%P 1226-1235
%V 24
%N 5
%X Localized, brief Ca2+ transients (Ca2+ syntillas) caused by release from intracellular stores were found in isolated nerve terminals from magnocellular hypothalamic neurons and examined quantitatively using a signal mass approach to Ca2+ imaging. Ca2+ syntillas (scintilla, L., spark, from a synaptic structure, a nerve terminal) are caused by release of ∼250,000 Ca ions on average by a Ca2+ flux lasting on the order of tens of milliseconds and occur spontaneously at a membrane potential of –80 mV. Syntillas are unaffected by removal of extracellular Ca2+, are mediated by ryanodine receptors (RyRs) and are increased in frequency, in the absence of extracellular Ca2+, by physiological levels of depolarization. This represents the first direct demonstration of mobilization of Ca2+ from intracellular stores in neurons by depolarization without Ca2+ influx. The regulation of syntillas by depolarization provides a new link between neuronal activity and cytosolic [Ca2+] in nerve terminals.
%U https://www.jneurosci.org/content/jneuro/24/5/1226.full.pdf