Abstract
Despite widespread interest in dendritic spines, little is known about the mechanisms responsible for spine formation, retraction, or stabilization. We have now found that a brief exposure of cultured hippocampal neurons to a conditioning medium that favors activation of the NMDA receptor produces long-term modification of their spontaneous network activity. The conditioning protocol enhances correlated activity of neurons in the culture, in a process requiring an increase in [Ca(2+)](i) and is associated with both formation of novel dendritic spines and pruning of others. The novel spines are likely to be touched by a presynaptic terminal, labeled with FM4-64 dye, whereas the absence of such terminals increases the likelihood of spine pruning. These results indicate that long-term functional changes are correlated with morphological modifications of dendritic spines of neurons in a network.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, Non-P.H.S.
MeSH terms
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2-Amino-5-phosphonovalerate / pharmacology
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Animals
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Cells, Cultured
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Culture Media, Conditioned / pharmacology
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Dendrites / drug effects
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Dendrites / metabolism*
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Dendrites / ultrastructure
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Egtazic Acid / analogs & derivatives*
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Egtazic Acid / pharmacology
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Excitatory Amino Acid Antagonists / pharmacology
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Excitatory Postsynaptic Potentials / drug effects
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Fluorescent Dyes
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Hippocampus / cytology
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Hippocampus / drug effects
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Hippocampus / metabolism*
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Nerve Net / cytology
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Nerve Net / drug effects
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Nerve Net / physiology
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Neuronal Plasticity / physiology*
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Neurons / cytology
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Neurons / drug effects
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Neurons / metabolism*
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Patch-Clamp Techniques
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Pyridinium Compounds
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Quaternary Ammonium Compounds
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Rats
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Receptors, N-Methyl-D-Aspartate / antagonists & inhibitors
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Synapses / metabolism
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Synapses / ultrastructure
Substances
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Culture Media, Conditioned
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Excitatory Amino Acid Antagonists
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FM 4-64
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Fluorescent Dyes
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Pyridinium Compounds
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Quaternary Ammonium Compounds
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Receptors, N-Methyl-D-Aspartate
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1,2-bis(2-aminophenoxy)ethane N,N,N',N'-tetraacetic acid acetoxymethyl ester
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Egtazic Acid
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2-Amino-5-phosphonovalerate