title: Immunoelectron microscopic analysis of neurotoxic effect of glutamate in the vestibular end organs during ischemia.
abstract: CONCLUSIONS
  The excessive glutamate released from the type I and type II hair cells and the supporting cells injure the bouton-type endings and the nerve chalices in 30 min ischemia, and neuronal damage of glutamate was slight in 10 min ischemia.
  
  
  OBJECTIVE
  In the present study, we investigated by means of post-embedding immunoelectron microscopic analysis whether neuronal damage in the vestibular end organs is associated with the change of cellular glutamate concentration during ischemia.
  
  
  METHODS
  Transient local anoxia (10 min, 30 min) of guinea pig inner ear was induced by pressing the left labyrinthine artery. The right sides were used as controls. The morphological changes of the vestibular end organs and the areal gold particle densities representing glutamate were compared in the ischemia side and the control side.
  
  
  RESULTS
  The areal gold particle densities of the type I and type II hair cells and the supporting cells in the ischemic side were lower than those of the control side. There were no remarkable morphological changes compared to the control side in 10 min ischemia. In 30 min ischemia, the bouton-type endings were swollen and intercellular spaces between the type I hair cells and the nerve chalices were enlarged.
authors.affiliation: Department of Otorhinolaryngology, Hirosaki University Graduate School of Medicine, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Sasaki
authors.forename: Atsushi
authors.initials: A
authors.lastname: Matsubara
authors.forename: Keiji
authors.initials: K
authors.lastname: Tabuchi
authors.forename: Akira
authors.initials: A
authors.lastname: Hara
authors.forename: Atsushi
authors.initials: A
authors.lastname: Namba
authors.forename: Youhei
authors.initials: Y
authors.lastname: Yamamoto
authors.forename: Hideichi
authors.initials: H
authors.lastname: Shinkawa
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D018698:Glutamic Acid / Q000378:metabolism*; D006168:Guinea Pigs; D006199:Hair Cells, Auditory, Inner / Q000378:metabolism / Q000473:pathology*; D007511:Ischemia / Q000209:etiology / Q000378:metabolism* / Q000473:pathology; D016253:Microscopy, Immunoelectron; D017729:Presynaptic Terminals / Q000378:metabolism / Q000473:pathology*; D012307:Risk Factors; D013997:Time Factors; D014722:Vestibule, Labyrinth / Q000098:blood supply / Q000378:metabolism* / Q000473:pathology*
chemical_list: D018698:Glutamic Acid