Abstract
A single neurotransmitter elicits diverse physiological responses through activation of multiple receptor subtypes and/or heterosynaptic interactions involving distinct synaptic targets. We found that a typical excitatory transmitter released from the climbing fiber (CF) in the cerebellar cortex not only excited Purkinje cells directly but also presynaptically inhibited GABAergic transmission from interneurons converging on the same Purkinje cells. Both homosynaptic and heterosynaptic actions of the CF transmitter (possibly glutamate) were mediated by activation of AMPA receptors. Dual AMPA receptor-mediated functions of excitation and disinhibition may ensure transmission of cerebellar CF signals controlling sensorimotor coordination.
MeSH terms
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Animals
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Cell Membrane / metabolism
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Cerebellum / cytology
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Cerebellum / metabolism*
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Chelating Agents / pharmacology
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Colforsin / pharmacology
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Egtazic Acid / analogs & derivatives
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Egtazic Acid / pharmacology
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Electric Stimulation
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Excitatory Amino Acid Antagonists / pharmacology
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Excitatory Postsynaptic Potentials / drug effects
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Excitatory Postsynaptic Potentials / physiology
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In Vitro Techniques
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Interneurons / cytology
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Interneurons / metabolism*
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Microelectrodes
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Nerve Fibers / drug effects
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Nerve Fibers / metabolism
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Neural Inhibition / drug effects
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Neural Inhibition / physiology
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Patch-Clamp Techniques
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Purkinje Cells / cytology
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Purkinje Cells / drug effects
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Purkinje Cells / metabolism
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Rats
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Rats, Wistar
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Receptors, AMPA / antagonists & inhibitors
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Receptors, AMPA / metabolism*
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Synapses / metabolism*
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gamma-Aminobutyric Acid / metabolism*
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gamma-Aminobutyric Acid / pharmacology
Substances
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Chelating Agents
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Excitatory Amino Acid Antagonists
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Receptors, AMPA
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Colforsin
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Egtazic Acid
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gamma-Aminobutyric Acid
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1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid