Department of Physiology
Animals; Caffeine; Calcium; Calcium Signaling; Hypothalamus; Membrane Potentials; Mice; Neurons; Patch-Clamp Techniques; Presynaptic Terminals; Ryanodine Receptor Calcium Release Channel; Subcellular Fractions
Life Sciences | Medicine and Health Sciences | Neuroscience and Neurobiology
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 approximately 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.
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Citation: J Neurosci. 2004 Feb 4;24(5):1226-35. Link to article on publisher's site
DOI of Published Version
The Journal of neuroscience : the official journal of the Society for Neuroscience
De Crescenzo, Valerie; ZhuGe, Ronghua; Velazquez-Marrero, Cristina M.; Lifshitz, Lawrence M.; Custer, Edward E.; Carmichael, Jeffrey; Lai, F. Anthony; Tuft, Richard A.; Fogarty, Kevin E.; Lemos, Jose R.; and Walsh, John V., "Ca2+ syntillas, miniature Ca2+ release events in terminals of hypothalamic neurons, are increased in frequency by depolarization in the absence of Ca2+ influx" (2004). Open Access Articles. 1172.