title: Presynaptically expressed long-term depression at cerebellar parallel fiber synapses.
abstract: Plasticity at synapses between parallel fiber (PF) and Purkinje neurons (PN) is widely accepted as a cellular model for certain forms of cerebellar learning. Although PF-PN synapses are known to express bidirectional long-term plasticity at the postsynaptic site, long-term plasticity at the presynaptic site is currently limited to potentiation of the synapses. In this paper, we report on presynaptically expressed PF long-term depression (preLTD) that is observed when presynaptically expressed PF long-term potentiation (preLTP) is pharmacologically prevented. PF preLTD is most efficiently induced by 4 Hz PF stimulation and requires activation of cannabinoid CB1 receptors. Our results indicate that, during preLTD induction, endocannabinoids are released in an NMDA receptor-dependent, but not mGlu1 receptor-dependent, fashion. We conclude that bidirectional plasticity mechanisms exist for both presynaptic and postsynaptic components of cerebellar learning.
authors.affiliation: Laboratory for Neuronal Circuit Dynamics, RIKEN Brain Science Institute, 2-1 Hirosawa, Wako-shi, Saitama, 351-0198, Japan.
authors.forename: De-lai
authors.initials: DL
authors.lastname: Qiu
authors.forename: Thomas
authors.initials: T
authors.lastname: Knöpfel
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism; D063385:Cannabinoid Receptor Modulators / Q000378:metabolism; D002531:Cerebellum / Q000166:cytology / Q000378:metabolism; D058788:GABA-B Receptor Antagonists; D036881:Long-Term Synaptic Depression / Q000502:physiology*; D051379:Mice; D008822:Mice, Transgenic; D009473:Neuronal Plasticity / Q000502:physiology*; D009569:Nitric Oxide / Q000378:metabolism; D018408:Patch-Clamp Techniques; D017729:Presynaptic Terminals / Q000502:physiology*; D043884:Receptor, Cannabinoid, CB1 / Q000037:antagonists & inhibitors / Q000378:metabolism; D018080:Receptors, GABA-B / Q000378:metabolism; D018094:Receptors, Metabotropic Glutamate / Q000037:antagonists & inhibitors / Q000378:metabolism; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors / Q000378:metabolism; D013569:Synapses / Q000378:metabolism*
chemical_list: D063385:Cannabinoid Receptor Modulators; D058788:GABA-B Receptor Antagonists; D043884:Receptor, Cannabinoid, CB1; D018080:Receptors, GABA-B; D018094:Receptors, Metabotropic Glutamate; D016194:Receptors, N-Methyl-D-Aspartate; C104077:metabotropic glutamate receptor type 1; D009569:Nitric Oxide; D002118:Calcium; C108823:metabotropic glutamate receptor 4