Plasticity-dependent changes in metabotropic glutamate receptor expression at excitatory hippocampal synapses.
Group I metabotropic glutamate receptors, mGluR1 and mGluR5, modulate NMDA receptor-mediated synaptic transmission and plasticity and mediate mGluR-dependent plasticity. Here we report that the synaptic expression of mGluRs can be regulated by NMDA receptor-dependent synaptic plasticity, but that this is dependent on the subtype of mGluR. Silent synapses, but not active synapses, were found to lack Group I mGluRs showing that mGluRs must be inserted into synapses after they are unsilenced. The induction of LTP resulted in an increased synaptic expression of mGluR1 in an NMDA receptor-dependent manner. mGluR1 is internalized from synapses via NMDA receptor-dependent LTD. Interestingly we found no evidence for the regulation of mGluR5 by NMDA receptor-dependent plasticity. This regulation of Group I mGluRs will determine the ability of synapses to undergo mGluR-dependent modulation of synaptic transmission and plasticity, providing a mechanism for metaplasticity and state-dependent plasticity at hippocampal synapses.
Cheyne
Juliette E
JE
Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand.
Montgomery
Johanna M
JM
D015763:2-Amino-5-phosphonovalerate / Q000494:pharmacology; D000818:Animals; D000831:Animals, Newborn; D002478:Cells, Cultured; D004558:Electric Stimulation / Q000379:methods; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D049452:Green Fluorescent Proteins / Q000235:genetics; D006624:Hippocampus / Q000166:cytology*; D017774:Long-Term Potentiation / Q000502:physiology; D036881:Long-Term Synaptic Depression / Q000502:physiology; D009473:Neuronal Plasticity / Q000502:physiology*; D009474:Neurons / Q000502:physiology*; D018408:Patch-Clamp Techniques; D021381:Protein Transport / Q000502:physiology; D051381:Rats; D064529:Receptor, Metabotropic Glutamate 5; D018094:Receptors, Metabotropic Glutamate / Q000378:metabolism*; D013569:Synapses / Q000502:physiology*; D016704:Synapsins / Q000378:metabolism; D009435:Synaptic Transmission / Q000502:physiology; D014162:Transfection / Q000379:methods
D018691:Excitatory Amino Acid Antagonists; C578937:Grm5 protein, rat; D064529:Receptor, Metabotropic Glutamate 5; D018094:Receptors, Metabotropic Glutamate; D016704:Synapsins; C104077:metabotropic glutamate receptor type 1; D049452:Green Fluorescent Proteins; D015763:2-Amino-5-phosphonovalerate