Abstract
We investigated the roles of ionotropic glutamate receptor subtypes in the development and recovery of spontaneous nystagmus (SN) after unilateral labyrinthectomy (UL) in guinea pigs. When administered at 3 h after UL, N-methyl-D-aspartate (NMDA) and kainate (KA), which are NMDA and non-NMDA receptor agonists, respectively, increased the frequency of SN. The effect of KA was more potent than that of NMDA. In contrast to these agonists, MK-801 and CNQX decreased the frequency of SN. Although the administration of KA at 48 h after UL increased the frequency of SN, it did not exhibit any effects at 72 h after UL. MK-801 caused a recurrence of SN following administration at 48 and 72 h after UL. Neither NMDA nor CNQX exhibited any effects after administration at 48 or 72 h after UL. A newly synthesized compound, NC-1200, which has inhibitory action on the glutamate response, decreased the frequency of SN in a dose-dependent manner following administration at 3 h after UL, but did not exhibit any effects when administered at 48 and 72 h after UL. From these results, it was found that NMDA and non-NMDA receptors play important roles in the development of SN after UL, and that the NMDA receptor contributes to the development of ocular motor compensation.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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6-Cyano-7-nitroquinoxaline-2,3-dione / pharmacology
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Animals
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Azepines / pharmacology
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Denervation / adverse effects*
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Dizocilpine Maleate / pharmacology
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Dose-Response Relationship, Drug
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Ear, Inner / surgery*
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Functional Laterality / drug effects
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Functional Laterality / physiology
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Guinea Pigs
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Kainic Acid / pharmacology
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Male
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Muscle Relaxants, Central / pharmacology
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N-Methylaspartate / pharmacology
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Neuronal Plasticity / drug effects*
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Neuronal Plasticity / physiology
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Nystagmus, Pathologic / etiology*
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Nystagmus, Pathologic / pathology
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Nystagmus, Pathologic / physiopathology
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Oxazolidinones / pharmacology
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Receptors, Glutamate / classification
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Receptors, Glutamate / drug effects*
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Receptors, Glutamate / metabolism
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Receptors, N-Methyl-D-Aspartate / drug effects
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Receptors, N-Methyl-D-Aspartate / metabolism
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Recovery of Function / drug effects*
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Recovery of Function / physiology
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Time Factors
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Vestibular Nerve / drug effects
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Vestibular Nerve / physiology
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Vestibular Nerve / surgery*
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Vestibular Nuclei / cytology
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Vestibular Nuclei / drug effects
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Vestibular Nuclei / metabolism
Substances
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Azepines
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Muscle Relaxants, Central
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Oxazolidinones
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Receptors, Glutamate
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Receptors, N-Methyl-D-Aspartate
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MLV 6976
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N-Methylaspartate
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Dizocilpine Maleate
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6-Cyano-7-nitroquinoxaline-2,3-dione
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Kainic Acid