Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6798
pubmed:dateCreated
2000-9-14
pubmed:abstractText
Calcium-triggered fusion of synaptic vesicles and neurotransmitter release are fundamental signalling steps in the central nervous system. It is generally assumed that fast transmitter release is triggered by elevations in intracellular calcium concentration ([Ca2+]i) to at least 100 microM near the sites of vesicle fusion. For synapses in the central nervous system, however, there are no experimental estimates of this local [Ca2+]i signal. Here we show, by using calcium ion uncaging in the large synaptic terminals of the calyx of Held, that step-like elevations to only 10 microM [Ca2+]i induce fast transmitter release, which depletes around 80% of a pool of available vesicles in less than 3 ms. Kinetic analysis of transmitter release rates after [Ca2+]i steps revealed the rate constants for calcium binding and vesicle fusion. These show that transient (around 0.5 ms) local elevations of [Ca2+]i to peak values as low as 25 microM can account for transmitter release during single presynaptic action potentials. The calcium sensors for vesicle fusion are far from saturation at normal release probability. This non-saturation, and the high intracellular calcium cooperativity in triggering vesicle fusion, make fast synaptic transmission very sensitive to modulation by changes in local [Ca2+]i.
pubmed:commentsCorrections
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0028-0836
pubmed:author
pubmed:issnType
Print
pubmed:day
24
pubmed:volume
406
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
889-93
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2000
pubmed:articleTitle
Intracellular calcium dependence of transmitter release rates at a fast central synapse.
pubmed:affiliation
Abteilung Membranbiophysik, Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany. rschneg@gwdg.de
pubmed:publicationType
Journal Article, In Vitro, Research Support, Non-U.S. Gov't