Modulation of presynaptic calcium transients by metabotropic glutamate receptor activation: A differential role in acute depression of synaptic transmission and long-term depression

Guido C. Faas, Hita Adwanikar, Robert W. Gereau IV, Peter Saggau

Research output: Contribution to journalArticlepeer-review

84 Scopus citations

Abstract

Activation of group I metabotropic glutamate receptors (mGluRs) can induce acute depression of excitatory synaptic transmission and long-term depression (LTD) in area CA1 of the rat hippocampus. The underlying mechanisms for both forms of depression are unknown. By measuring presynaptic calcium transients, we show that a reduction in the stimulation-induced presynaptic calcium rise that triggers vesicular release causes the acute depression of transmission by group I mGluRs. In contrast, the mechanism underlying mGluR-induced LTD does not involve a persistent change in stimulation-induced calcium influx. However, analysis of paired-pulse facilitation experiments suggests a presynaptic location for expression of this form of LTD. Furthermore, we show that mGluR-induced LTD can be completely blocked by a specific mGluR5 antagonist, whereas mGluR1 antagonists strongly attenuate the acute depression of transmission. These results support the hypothesis that the acute depression of transmission caused by activation of group I mGluRs involves regulation of stimulation-induced presynaptic calcium transients, whereas mGluR-induced LTD involves a distinct presynaptic modulation downstream of calcium influx.

Original languageEnglish
Pages (from-to)6885-6890
Number of pages6
JournalJournal of Neuroscience
Volume22
Issue number16
DOIs
StatePublished - Aug 15 2002

Keywords

  • Calcium
  • DHPG
  • Hippocampus
  • LTD
  • Presynaptic
  • mGluR

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