Microdomains of high calcium concentration in a presynaptic terminal

R. Llinás, M. Sugimori, R. B. Silver

Research output: Contribution to journalArticlepeer-review

741 Scopus citations


Increases in intracellular calcium concentration are required for the release of neurotransmitter from presynaptic terminals in all neurons. However, the mechanism by which calcium exerts its effect is not known. A low-sensitivity calcium-dependent photoprotein (n-aequorin-J) was injected into the presynaptic terminal of the giant squid synapse to selectively detect high calcium concentration microdomains. During transmitter release, light emission occurred at specific points or quantum emission domains that remained in the same place during protracted stimulation. Intracellular calcium concentration microdomains on the order of 200 to 300 micromolar occur against the cytoplasmic surface of the plasmalemma during transmitter secretion, supporting the view that the synaptic vesicular fusion responsible for transmitter release is triggered by the activation of a low-affinity calcium-binding site at the active zone.

Original languageEnglish (US)
Pages (from-to)677-679
Number of pages3
Issue number5057
StatePublished - 1992
Externally publishedYes

ASJC Scopus subject areas

  • General


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