title: Alterations of the electroretinogram by intravitreal kainic acid in the rat.
abstract: OBJECTIVE
  To relate the electrophysiological changes in the retina induced by the excitatory neurotoxin, kainic acid (KA), to its receptor sites in the rat.
  
  
  METHODS
  Fifty-five Wistar rats were injected intravitreally with 100, 50, 25, 12.5, 6.25, 3.12, or 1.56 nmol of KA. The electroretinograms (ERGs) including oscillatory potentials (OPs) elicited by a series of increasing intensities were recorded before, and 6 hours, 1 day, 1 week, and 1 month after the injection of KA.
  
  
  RESULTS
  After KA injection, the a-waves showed no significant change at all intensity levels (P > .05), but the amplitudes and implicit times of the b-wave were significantly altered. The abolition of the b-wave by KA resulted in a negative response, which decreased progressively with time. The implicit times of the b-wave showed a marked prolongation after injection of 100 nmol of KA (P < .01). The OPs disappeared at the KA dose of 6.25 nmol and higher; doses of 1.56 to 3.12 nmol of KA depressed the Ops.
  
  
  CONCLUSIONS
  We conclude that KA altered the above-mentioned ERG components in a dose-dependent manner. These alterations of the ERG can be explained by alterations of neurons in the inner retinal layers.
authors.affiliation: Department of Ophthalmology, Chiba University School of Medicine, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Li
authors.forename: A
authors.initials: A
authors.lastname: Mizota
authors.forename: E
authors.initials: E
authors.lastname: Adachi-Usami
mesh_terms: D000818:Animals; D004305:Dose-Response Relationship, Drug; D004596:Electroretinography / Q000187:drug effects*; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology*; D005260:Female; D007267:Injections; D007608:Kainic Acid / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D012160:Retina / Q000187:drug effects* / Q000502:physiology; D014822:Vitreous Body
chemical_list: D018690:Excitatory Amino Acid Agonists; D007608:Kainic Acid