Spontaneous neurotransmission signals through store-driven Ca<sup>2+</sup> transients to maintain synaptic homeostasis

Austin L. Reese, Ege T. Kavalali

Research output: Contribution to journalArticle

29 Scopus citations

Abstract

Spontaneous glutamate release-driven NMDA receptor activity exerts a strong influence on synaptic homeostasis. However, the properties of Ca<sup>2+</sup> signals that mediate this effect remain unclear. Here, using hippocampal neurons labeled with the fluorescent Ca<sup>2+</sup>+ probes Fluo-4 or GCAMP5, we visualized action potential-independent Ca<sup>2+</sup>+ transients in dendritic regions adjacent to fluorescently labeled presynaptic boutons in physiological levels of extracellular Mg2+. These Ca<sup>2+</sup>+ transients required NMDA receptor activity, and their propensity correlated with acute or genetically induced changes in spontaneous neurotransmitter release. In contrast, they were insensitive to blockers of AMPA receptors, L-type voltage-gated Ca<sup>2+</sup>+ channels, or group I mGluRs. However, inhibition of Ca<sup>2+</sup>+-induced Ca<sup>2+</sup>+ release suppressed these transients and elicited synaptic scaling, a process which required protein translation and eukaryotic elongation factor-2 kinase activity. These results support a critical role for Ca<sup>2+</sup>+-induced Ca<sup>2+</sup>+ release in amplifying NMDA receptor-driven Ca<sup>2+</sup>+ signals at rest for the maintenance of synaptic homeostasis.

Original languageEnglish (US)
JournaleLife
Volume4
Issue numberJULY2015
DOIs
StatePublished - Jul 24 2015

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Immunology and Microbiology(all)
  • Medicine(all)
  • Neuroscience(all)

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