Abstract
The mossy fiber to CA3 pyramidal cell synapse (mf-CA3) provides a major source of excitation to the hippocampus. Thus far, these glutamatergic synapses are well recognized for showing a presynaptic, NMDA receptor-independent form of LTP that is expressed as a long-lasting increase of transmitter release. Here, we show that in addition to this "classical" LTP, mf-CA3 synapses can undergo a form of LTP characterized by a selective enhancement of NMDA receptor-mediated transmission. This potentiation requires coactivation of NMDA and mGlu5 receptors and a postsynaptic calcium rise. Unlike classical LTP, expression of this mossy fiber LTP is due to a PKC-dependent recruitment of NMDA receptors specifically to the mf-CA3 synapse via a SNARE-dependent process. Having two mechanistically different forms of LTP may allow mf-CA3 synapses to respond with more flexibility to the changing demands of the hippocampal network.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Animals, Newborn
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Dose-Response Relationship, Radiation
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Egtazic Acid / analogs & derivatives
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Egtazic Acid / pharmacology
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Electric Stimulation / methods
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Enzyme Inhibitors / pharmacology
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Excitatory Amino Acid Antagonists / pharmacology
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GTP-Binding Proteins / deficiency
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Guanosine 5'-O-(3-Thiotriphosphate) / pharmacology
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Hippocampus / cytology*
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In Vitro Techniques
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Long-Term Potentiation / drug effects
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Long-Term Potentiation / physiology*
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Long-Term Potentiation / radiation effects
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Mice
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Mice, Knockout
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Mossy Fibers, Hippocampal / physiology*
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Patch-Clamp Techniques / methods
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Rats
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Rats, Wistar
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Receptors, N-Methyl-D-Aspartate / physiology*
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Synapses / physiology
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Synaptic Transmission / drug effects
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Synaptic Transmission / physiology
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Synaptic Transmission / radiation effects
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Synaptosomal-Associated Protein 25 / pharmacology
Substances
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Enzyme Inhibitors
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Excitatory Amino Acid Antagonists
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Receptors, N-Methyl-D-Aspartate
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Rims1 protein, mouse
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Synaptosomal-Associated Protein 25
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Guanosine 5'-O-(3-Thiotriphosphate)
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Egtazic Acid
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GTP-Binding Proteins
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1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid