title: Roles of glutamate receptor subtypes in the development of vestibular compensation after unilateral labyrinthectomy in the guinea pig.
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.
authors: Research Laboratories, Nippon Chemiphar Co. Ltd., Misato, 341-0005, Saitama, Japan. nchirate@green.ocn.ne.jp
authors: K
authors: K
authors: Hirate
authors: A
authors: A
authors: Kitayama
authors: N
authors: N
authors: Furuya
mesh_terms: D018750:6-Cyano-7-nitroquinoxaline-2,3-dione / Q000494:pharmacology; D000818:Animals; D001381:Azepines / Q000494:pharmacology; D003714:Denervation / Q000009:adverse effects*; D016291:Dizocilpine Maleate / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D007758:Ear, Inner / Q000601:surgery*; D007839:Functional Laterality / Q000187:drug effects / Q000502:physiology; D006168:Guinea Pigs; D007608:Kainic Acid / Q000494:pharmacology; D008297:Male; D009125:Muscle Relaxants, Central / Q000494:pharmacology; D016202:N-Methylaspartate / Q000494:pharmacology; D009473:Neuronal Plasticity / Q000187:drug effects* / Q000502:physiology; D009759:Nystagmus, Pathologic / Q000209:etiology* / Q000473:pathology / Q000503:physiopathology; D023303:Oxazolidinones / Q000494:pharmacology; D017470:Receptors, Glutamate / Q000145:classification / Q000187:drug effects* / Q000378:metabolism; D016194:Receptors, N-Methyl-D-Aspartate / Q000187:drug effects / Q000378:metabolism; D020127:Recovery of Function / Q000187:drug effects* / Q000502:physiology; D013997:Time Factors; D014725:Vestibular Nerve / Q000187:drug effects / Q000502:physiology / Q000601:surgery*; D014726:Vestibular Nuclei / Q000166:cytology / Q000187:drug effects / Q000378:metabolism
chemical_list: D001381:Azepines; D009125:Muscle Relaxants, Central; D023303:Oxazolidinones; D017470:Receptors, Glutamate; D016194:Receptors, N-Methyl-D-Aspartate; C051400:MLV 6976; D016202:N-Methylaspartate; D016291:Dizocilpine Maleate; D018750:6-Cyano-7-nitroquinoxaline-2,3-dione; D007608:Kainic Acid