Abstract
Early visual experience is essential in the refinement of developing neural connections. In vivo whole-cell recording from the tectum of Xenopus tadpoles showed that repetitive dimming-light stimulation applied to the contralateral eye resulted in persistent enhancement of glutamatergic inputs, but not GABAergic or glycinergic inputs, on tectal neurons. This enhancement can be attributed to potentiation of retinotectal synapses. It required spiking of postsynaptic tectal cells as well as activation of NMDA receptors, and effectively occluded long-term potentiation (LTP) of retinotectal synapses induced by direct electrical stimulation of retinal ganglion cells. Thus, LTP-like synaptic modification can be induced by natural visual inputs and may be part of the underlying mechanism for the activity-dependent refinement of developing connections.
Publication types
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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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6-Cyano-7-nitroquinoxaline-2,3-dione / pharmacology
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Animals
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Bicuculline / analogs & derivatives
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Bicuculline / pharmacology
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Dicarboxylic Acids / pharmacology
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Light
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Long-Term Potentiation / drug effects
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Long-Term Potentiation / physiology*
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Neurons / drug effects
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Neurons / physiology*
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Neurotransmitter Uptake Inhibitors / pharmacology
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Photic Stimulation
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Pyrrolidines / pharmacology
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Retina / physiology*
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Superior Colliculi / drug effects
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Superior Colliculi / physiology*
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Synapses / drug effects
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Synapses / physiology*
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Visual Pathways / physiology*
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Visual Perception / physiology
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Xenopus
Substances
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Dicarboxylic Acids
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Neurotransmitter Uptake Inhibitors
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Pyrrolidines
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bicuculline methiodide
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6-Cyano-7-nitroquinoxaline-2,3-dione
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2-Amino-5-phosphonovalerate
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pyrrolidine-2,4-dicarboxylic acid
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Bicuculline