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.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Calcium / metabolism
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Cannabinoid Receptor Modulators / metabolism
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Cerebellum* / cytology
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Cerebellum* / metabolism
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GABA-B Receptor Antagonists
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Long-Term Synaptic Depression / physiology*
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Mice
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Mice, Transgenic
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Neuronal Plasticity / physiology*
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Nitric Oxide / metabolism
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Patch-Clamp Techniques
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Presynaptic Terminals / physiology*
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Receptor, Cannabinoid, CB1 / antagonists & inhibitors
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Receptor, Cannabinoid, CB1 / metabolism
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Receptors, GABA-B / metabolism
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Receptors, Metabotropic Glutamate / antagonists & inhibitors
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Receptors, Metabotropic Glutamate / metabolism
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Receptors, N-Methyl-D-Aspartate / antagonists & inhibitors
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Receptors, N-Methyl-D-Aspartate / metabolism
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Synapses / metabolism*
Substances
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Cannabinoid Receptor Modulators
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GABA-B Receptor Antagonists
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Receptor, Cannabinoid, CB1
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Receptors, GABA-B
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Receptors, Metabotropic Glutamate
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Receptors, N-Methyl-D-Aspartate
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metabotropic glutamate receptor type 1
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Nitric Oxide
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Calcium
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metabotropic glutamate receptor 4