title: Long-term depression of mGluR1 signaling.
abstract: Glutamate produces both fast excitation through activation of ionotropic receptors and slower actions through metabotropic receptors (mGluRs). To date, ionotropic but not metabotropic neurotransmission has been shown to undergo long-term synaptic potentiation and depression. Burst stimulation of parallel fibers releases glutamate, which activates perisynaptic mGluR1 in the dendritic spines of cerebellar Purkinje cells. Here, we show that the mGluR1-dependent slow EPSC and its coincident Ca transient were selectively and persistently depressed by repeated climbing fiber-evoked depolarization of Purkinje cells in brain slices. LTD(mGluR1) was also observed when slow synaptic current was evoked by exogenous application of a group I mGluR agonist, implying a postsynaptic expression mechanism. Ca imaging further revealed that LTD(mGluR1) was expressed as coincident attenuation of both limbs of mGluR1 signaling: the slow EPSC and PLC/IP3-mediated dendritic Ca mobilization. Thus, different patterns of neural activity can evoke LTD of either fast ionotropic or slow mGluR1-mediated synaptic signaling.
authors.affiliation: Department of Physiology, Seoul National University College of Medicine and Neuroscience Research Institute Medical Research Center, Korea.
authors.forename: Yunju
authors.initials: Y
authors.lastname: Jin
authors.forename: Sang Jeong
authors.initials: SJ
authors.lastname: Kim
authors.forename: Jun
authors.initials: J
authors.lastname: Kim
authors.forename: Paul F
authors.initials: PF
authors.lastname: Worley
authors.forename: David J
authors.initials: DJ
authors.lastname: Linden
mesh_terms: D000818:Animals; D020013:Calcium Signaling / Q000502:physiology; D019706:Excitatory Postsynaptic Potentials / Q000502:physiology*; D066298:In Vitro Techniques; D036881:Long-Term Synaptic Depression / Q000502:physiology*; D009412:Nerve Fibers / Q000378:metabolism; D018408:Patch-Clamp Techniques; D011689:Purkinje Cells / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D018094:Receptors, Metabotropic Glutamate / Q000378:metabolism*; D009435:Synaptic Transmission / Q000502:physiology*
chemical_list: D018094:Receptors, Metabotropic Glutamate; C104077:metabotropic glutamate receptor type 1