November 1996
Volume 37, Issue 12
Free
Articles  |   November 1996
Systemic L-kynurenine administration partially protects against NMDA, but not kainate-induced degeneration of retinal ganglion cells, and reduces visual discrimination deficits in adults rats.
Author Affiliations
  • C K Vorwerk
    Institute of Medical Psychology, Medical Faculty, Otto-von-Guericke-University of Magdeburg, Germany.
  • M R Kreutz
    Institute of Medical Psychology, Medical Faculty, Otto-von-Guericke-University of Magdeburg, Germany.
  • E B Dreyer
    Institute of Medical Psychology, Medical Faculty, Otto-von-Guericke-University of Magdeburg, Germany.
  • B A Sabel
    Institute of Medical Psychology, Medical Faculty, Otto-von-Guericke-University of Magdeburg, Germany.
Investigative Ophthalmology & Visual Science November 1996, Vol.37, 2382-2392. doi:
  • Views
  • PDF
  • Share
  • Tools
    • Alerts
      ×
      This feature is available to authenticated users only.
      Sign In or Create an Account ×
    • Get Citation

      C K Vorwerk, M R Kreutz, E B Dreyer, B A Sabel; Systemic L-kynurenine administration partially protects against NMDA, but not kainate-induced degeneration of retinal ganglion cells, and reduces visual discrimination deficits in adults rats.. Invest. Ophthalmol. Vis. Sci. 1996;37(12):2382-2392.

      Download citation file:


      © ARVO (1962-2015); The Authors (2016-present)

      ×
  • Supplements
Abstract

PURPOSE: Kynurenic acid (KYNA), an endogenous tryptophan metabolite, is an N-methyl-D-aspartate (NMDA) antagonist active at the glycine-binding site of the NMDA-receptor complex. The authors investigated whether systemic administration of a biochemical precursor of KYNA, L-kynurenine (L-Kyn), could block NMDA- or kainic acid (KA)-induced cell death in adult rat retinal ganglion cells (RGCs) and protect NMDA-treated animals from lesion-induced visual deficits. METHODS: Rats were injected with 20-nmol NMDA or 5-nmol KA intraocularly. To quantify the number of surviving RGCs, the retrograde tracer horseradish-peroxidase was injected into the superior colliculus contralateral to the lesioned eye. Surviving RGCs were counted on wholemounted retinae in a centroperipheral gradient, as well as in the four quadrants, using a computer-assisted image analysis system. RESULTS: The NMDA-injections resulted in an approximately 82% RGC loss in the adult rat retina compared with control retinae and a cell loss of approximately 50% in KA-treated retinae. Pretreatment with L-Kyn significantly reduced NMDA-induced RGC degeneration to values of approximately 60%, but KA toxicity was not significantly affected by L-Kyn pretreatment. Intraocular injections of NMDA resulted in an impairment of visual discrimination behavior, which partially recovered within a period of approximately 3 weeks. However, when treated systemically with L-Kyn, brightness discrimination was significantly improved as compared with NMDA-treated rats. CONCLUSIONS: These findings show that systemic administration of L-Kyn in adult rats can block NMDA-induced retinal ganglion cell death in vivo and preserves brightness discrimination performance.

×
×

This PDF is available to Subscribers Only

Sign in or purchase a subscription to access this content. ×

You must be signed into an individual account to use this feature.

×