Abstract
Voltage-gated A-type K+ channel Kv4.2 subunits are highly expressed in the dendrites of hippocampal CA1 neurons. However, little is known about the subcellular distribution and trafficking of Kv4.2-containing channels. Here we provide evidence for activity-dependent trafficking of Kv4.2 in hippocampal spines and dendrites. Live imaging and electrophysiological recordings showed that Kv4.2 internalization is induced rapidly upon glutamate receptor stimulation. Kv4.2 internalization was clathrin mediated and required NMDA receptor activation and Ca2+ influx. In dissociated hippocampal neurons, mEPSC amplitude depended on functional Kv4.2 expression level and was enhanced by stimuli that induced Kv4.2 internalization. Long-term potentiation (LTP) induced by brief glycine application resulted in synaptic insertion of GluR1-containing AMPA receptors along with Kv4.2 internalization. We also found evidence of Kv4.2 internalization upon synaptically evoked LTP in CA1 neurons of hippocampal slice cultures. These results present an additional mechanism for synaptic integration and plasticity through the activity-dependent regulation of Kv4.2 channel surface expression.
Publication types
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Research Support, N.I.H., Intramural
MeSH terms
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Actins / metabolism
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Animals
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Cells, Cultured
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Clathrin / metabolism
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Dendrites / drug effects
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Dendrites / physiology*
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Drug Interactions
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Embryo, Mammalian
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Excitatory Amino Acid Agonists / pharmacology
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Excitatory Postsynaptic Potentials / drug effects
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Excitatory Postsynaptic Potentials / physiology
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Excitatory Postsynaptic Potentials / radiation effects
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Glycine / 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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Mutagenesis, Site-Directed / methods
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Neurons / cytology*
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Neurons / physiology*
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Patch-Clamp Techniques / methods
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Potassium Channel Blockers / pharmacology
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Protein Transport / drug effects
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Protein Transport / physiology
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Rats
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Rats, Sprague-Dawley
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Shal Potassium Channels / genetics
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Shal Potassium Channels / metabolism*
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Transduction, Genetic / methods
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alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid / pharmacology
Substances
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Actins
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Clathrin
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Excitatory Amino Acid Agonists
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Potassium Channel Blockers
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Shal Potassium Channels
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alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid
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Glycine