Abstract
The effects of iontophoretically ejected glutamate receptor antagonists on mechanically evoked responsiveness were examined on wide dynamic range (WDR) dorsal horn neurons in anesthetized rats that received a unilateral ligation of the L5 and L6 spinal nerves 10-15 days previously. Both brush- and pinch-evoked responses of dorsal horn neurons on the nerve-injured side were enhanced. N-Methyl-D-aspartate (NMDA) receptor antagonist, 2-amino-5-phosphonopentanoic acid (AP5), preferentially suppressed the enhanced pinch-evoked response, whereas (RS)-a-amino-3-hydroxy-5-methyl-4-isoxazole-propionate (AMPA) receptor selective antagonist, 6-nitro-7-sulphamoylbenzo(f)quinoxaline-2,3-dione (NBQX), preferentially attenuated the enhanced brush-evoked response. The results indicate that the enhanced responses to noxious and non-noxious peripheral inputs induced in WDR dorsal horn neurons following the nerve injury are mediated by activation of NMDA and AMPA receptors, respectively.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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2-Amino-5-phosphonovalerate / pharmacology
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Animals
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Electrophysiology
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Excitatory Amino Acid Agonists / administration & dosage
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Excitatory Amino Acid Agonists / pharmacology
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Excitatory Amino Acid Antagonists / pharmacology*
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Iontophoresis
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Male
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N-Methylaspartate / administration & dosage
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N-Methylaspartate / pharmacology
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Neurons / drug effects
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Neurons / physiology*
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Peripheral Nerve Injuries*
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Physical Stimulation
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Quinoxalines / pharmacology
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Rats
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Rats, Sprague-Dawley
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Receptors, N-Methyl-D-Aspartate / antagonists & inhibitors*
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Spinal Cord / drug effects
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Spinal Cord / physiology*
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alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid / administration & dosage
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alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid / pharmacology
Substances
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Excitatory Amino Acid Agonists
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Excitatory Amino Acid Antagonists
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Quinoxalines
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Receptors, N-Methyl-D-Aspartate
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2,3-dioxo-6-nitro-7-sulfamoylbenzo(f)quinoxaline
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N-Methylaspartate
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2-Amino-5-phosphonovalerate
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alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid