Abstract
Argiotoxin, a component of the spider venom from Argiope lobata, blocks AMPA receptor channels expressed in homomeric and heteromeric configuration in Xenopus oocytes. Argiotoxin acts as an open channel blocker in a voltage-dependent manner and discriminates between the functionally diverse AMPA receptors. Importantly, a transmembrane region 2 determinant for divalent cation permeability also determines argiotoxin sensitivity. Subunit-specific differences in the time courses of block and recovery demonstrate that heteromeric AMPA receptors can assemble in variable ratios. Thus, argiotoxin can be used as a tool in analyzing the subunit composition of AMPA receptors in native membranes.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Base Sequence
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Cell Membrane / drug effects
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Cell Membrane / physiology
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Evoked Potentials / drug effects
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Female
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Indoleacetic Acids
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Ion Channels / drug effects
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Ion Channels / physiology*
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Kainic Acid / pharmacology
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Macromolecular Substances
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Molecular Sequence Data
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Mutagenesis
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Oligodeoxyribonucleotides
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Oocytes / drug effects
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Oocytes / physiology*
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Phenylacetates / pharmacology*
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Polyamines / pharmacology*
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Protein Conformation
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Receptors, AMPA
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Receptors, Glutamate / drug effects
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Receptors, Glutamate / genetics
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Receptors, Glutamate / physiology*
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Spider Venoms / pharmacology*
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Xenopus laevis
Substances
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Indoleacetic Acids
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Ion Channels
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Macromolecular Substances
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Oligodeoxyribonucleotides
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Phenylacetates
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Polyamines
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Receptors, AMPA
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Receptors, Glutamate
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Spider Venoms
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argiotoxin-636
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Kainic Acid