Abstract
Local GABA (gamma-aminobutyric acid) circuits contribute to sensory experience-dependent refinement of neuronal connections in the developing nervous system, but whether GABAergic synapses themselves can be rapidly modified by sensory stimuli is largely unknown. Here we report that repetitive light stimuli or theta burst stimulation (TBS) of the optic nerve in the developing Xenopus retinotectal system induces long-term potentiation (LTP) of glutamatergic inputs but long-term depression (LTD) of GABAergic inputs to the same tectal neuron. The LTD is due to a reduction in presynaptic GABA release and requires activation of presynaptic NMDA (N-methyl-D-aspartate) receptors (NMDARs) and coincident high-level GABAergic activity. Thus, the presynaptic NMDAR may function as a coincidence detector for adjacent glutamatergic and GABAergic activities, leading to coordinated synaptic modification by sensory experience.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Calcium Signaling / drug effects
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Calcium Signaling / physiology
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Excitatory Amino Acid Agonists / pharmacology
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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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Glutamic Acid / metabolism
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Larva
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Long-Term Synaptic Depression / drug effects
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Long-Term Synaptic Depression / physiology*
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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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Photic Stimulation
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Presynaptic Terminals / drug effects
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Presynaptic Terminals / metabolism*
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Receptors, N-Methyl-D-Aspartate / metabolism*
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Retina / cytology
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Retina / growth & development*
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Retina / metabolism
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Superior Colliculi / cytology
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Superior Colliculi / growth & development*
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Superior Colliculi / metabolism
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Synaptic Transmission / drug effects
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Synaptic Transmission / physiology
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Vision, Ocular / physiology
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Visual Pathways / cytology
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Visual Pathways / growth & development
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Visual Pathways / metabolism
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Xenopus laevis
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gamma-Aminobutyric Acid / metabolism*
Substances
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Excitatory Amino Acid Agonists
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Excitatory Amino Acid Antagonists
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Receptors, N-Methyl-D-Aspartate
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Glutamic Acid
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gamma-Aminobutyric Acid