mGluR2 postsynaptically senses granule cell inputs at Golgi cell synapses.
In the cerebellar circuit, Golgi cells are thought to contribute to information processing and integration via feedback mechanisms. In these mechanisms, dynamic modulation of Golgi cell excitability is necessary because GABA from Golgi cells causes tonic inhibition on granule cells. We studied the role and synaptic mechanisms of postsynaptic metabotropic glutamate receptor subtype 2 (mGluR2) at granule cell-Golgi cell synapses, using whole-cell recording of green fluorescent protein-positive Golgi cells of wild-type and mGluR2-deficient mice. Postsynaptic mGluR2 was activated by glutamate from granule cells and hyperpolarized Golgi cells via G protein-coupled inwardly rectifying K+ channels (GIRKs). This hyperpolarization conferred long-lasting silencing of Golgi cells, the duration and extents of which were dependent on stimulus strengths. Postsynaptic mGluR2 thus senses inputs from granule cells and is most likely important for spatiotemporal modulation of mossy fiber-granule cell transmission before distributing inputs to Purkinje cells.
Watanabe
Dai
D
Department of Biological Sciences, Kyoto University Faculty of Medicine, Kyoto 606-8501, Japan.
Nakanishi
Shigetada
S
D000818:Animals; D002531:Cerebellum / Q000166:cytology / Q000502:physiology; D004558:Electric Stimulation; D019706:Excitatory Postsynaptic Potentials / Q000502:physiology; D051676:G Protein-Coupled Inwardly-Rectifying Potassium Channels; D018698:Glutamic Acid / Q000378:metabolism; D049452:Green Fluorescent Proteins; D006801:Humans; D007150:Immunohistochemistry; D008164:Luminescent Proteins; D051379:Mice; D018345:Mice, Knockout; D008822:Mice, Transgenic; D009474:Neurons / Q000502:physiology*; D018408:Patch-Clamp Techniques; D015221:Potassium Channels / Q000378:metabolism; D024661:Potassium Channels, Inwardly Rectifying; D018091:Receptors, AMPA / Q000378:metabolism; D018094:Receptors, Metabotropic Glutamate / Q000172:deficiency / Q000502:physiology*; D013569:Synapses / Q000502:physiology*
D051676:G Protein-Coupled Inwardly-Rectifying Potassium Channels; D008164:Luminescent Proteins; D015221:Potassium Channels; D024661:Potassium Channels, Inwardly Rectifying; D018091:Receptors, AMPA; D018094:Receptors, Metabotropic Glutamate; C108822:metabotropic glutamate receptor 2; D049452:Green Fluorescent Proteins; D018698:Glutamic Acid