Activation of synaptic group II metabotropic glutamate receptors induces long-term depression at GABAergic synapses in CNS neurons.

Title

Activation of synaptic group II metabotropic glutamate receptors induces long-term depression at GABAergic synapses in CNS neurons.

Creator

Tang Zheng-Quan; Liu Yu-Wei; Shi Wei; Dinh Emilie Hoang; Hamlet William R; Curry Rebecca J; Lu Yong

Publisher

The Journal of neuroscience : the official journal of the Society for Neuroscience

Date

2013
2013-10

Description

Metabotropic glutamate receptor (mGluR)-dependent homosynaptic long-term depression (LTD) has been studied extensively at glutamatergic synapses in the CNS. However, much less is known about heterosynaptic long-term plasticity induced by mGluRs at inhibitory synapses. Here we report that pharmacological or synaptic activation of group II mGluRs (mGluR II) induces LTD at GABAergic synapses without affecting the excitatory glutamatergic transmission in neurons of the chicken cochlear nucleus. Coefficient of variation and failure rate analysis suggested that the LTD was expressed presynaptically. The LTD requires presynaptic spike activity, but does not require the activation of NMDA receptors. The classic cAMP-dependent protein kinase A signaling is involved in the transduction pathway. Remarkably, blocking mGluR II increased spontaneous GABA release, indicating the presence of tonic activation of mGluR II by ambient glutamate. Furthermore, synaptically released glutamate induced by electrical stimulations that concurrently activated both the glutamatergic and GABAergic pathways resulted in significant and constant suppression of GABA release at various stimulus frequencies (3.3, 100, and 300 Hz). Strikingly, low-frequency stimulation (1 Hz, 15 min) of the glutamatergic synapses induced heterosynaptic LTD of GABAergic transmission, and the LTD was blocked by mGluR II antagonist, indicating that synaptic activation of mGluR II induced the LTD. This novel form of long-term plasticity in the avian auditory brainstem may play a role in the development as well as in temporal processing in the sound localization circuit.

Subject

Animals; Chick Embryo; Synaptic Transmission/drug effects/*physiology; Excitatory Amino Acid Antagonists/pharmacology; Amino Acids/pharmacology; Cochlear Nucleus/drug effects/metabolism; Cyclopropanes/pharmacology; Excitatory Amino Acid Agonists/pharmacology; Excitatory Postsynaptic Potentials/drug effects/physiology; GABAergic Neurons/drug effects/*metabolism; Glycine/analogs & derivatives/pharmacology; Inhibitory Postsynaptic Potentials/drug effects/physiology; Long-Term Synaptic Depression/drug effects/*physiology; Neural Inhibition/drug effects/physiology; Synapses/drug effects/*metabolism; Xanthenes/pharmacology; Receptors; Metabotropic Glutamate/agonists/antagonists & inhibitors/*metabolism

Rights

Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).

Pages

15964–15977

Issue

40

Volume

33

Citation

Tang Zheng-Quan; Liu Yu-Wei; Shi Wei; Dinh Emilie Hoang; Hamlet William R; Curry Rebecca J; Lu Yong, “Activation of synaptic group II metabotropic glutamate receptors induces long-term depression at GABAergic synapses in CNS neurons.,” NEOMED Bibliography Database, accessed December 6, 2021, https://neomed.omeka.net/items/show/4991.

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