May 2007
Volume 48, Issue 13
ARVO Annual Meeting Abstract  |   May 2007
Hypothermia Reduces Retinal Injury in Ischemia/Reperfusion in Rats but GABAergic Agents Do Not
Author Affiliations & Notes
  • S. Traustason
    Department of Physiology, University of Iceland, Reykjavi­k, Iceland
  • T. Eysteinsson
    Department of Physiology,
    University of Iceland / Nat. Univ. Hospital, Reykjavi­k, Iceland
  • B. A. Agnarsson
    Department of Pathology,
    University of Iceland / Nat. Univ. Hospital, Reykjavi­k, Iceland
  • E. Stefansson
    Department of Ophthalmology,
    University of Iceland / Nat. Univ. Hospital, Reykjavi­k, Iceland
  • Footnotes
    Commercial Relationships S. Traustason, None; T. Eysteinsson, None; B.A. Agnarsson, None; E. Stefansson, None.
  • Footnotes
    Support Icelandic Fund for Prevention of Blindness, Landspítali University Hospital Research Fund, Helga Jonsdottir and Sigurlidi Kristjansson Memorial Fund
Investigative Ophthalmology & Visual Science May 2007, Vol.48, 2288. doi:
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    • Get Citation

      S. Traustason, T. Eysteinsson, B. A. Agnarsson, E. Stefansson; Hypothermia Reduces Retinal Injury in Ischemia/Reperfusion in Rats but GABAergic Agents Do Not. Invest. Ophthalmol. Vis. Sci. 2007;48(13):2288.

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

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To investigate the effect of reducing retinal metabolism with hypothermia or inhibitory GABAergic drugs on ischemia/ reperfusion (I/R) injury in the rat retina.


Rats were anaesthetised with ketamine and xylazine and pupils dilated. Following dark adaptation for 30 min a single-flash electroretinogram (ERG) was obtained. A needle was placed in the anterior chamber of the right eye to raise the intraocular pressure to 130 mmHg for 60 minutes. The left eye was untreated. After 10 days of reperfusion ERG recordings were obtained and eyes collected for histology.Each animal was injected with saline or a mixture of Baclofen/Midazolam or Baclofen/Muscimol 80 minutes prior to ischemia. The hypothermia group received a drip of cooled saline on the right eye during ischemia. A control group received only ischemia.


Retinal ganglion cells and inner nuclear layer cells decrease in number after I/R to 64±41% (mean ± SD, n=5, p = 0.12) and 64±45% (p = 0.15), respectively. Hypothermia protects the retina from I/R injury and the cell counts are 130±38% (p =0 .10) and 116±43% (n= 6, p =0 .41), respectively. GABA-ergic drugs do not prevent the I/R damage with cell counts 58±30% (n= 5, p =0 .069) and 20±33% (p = 0.035) and 80±27% (n=3, p = 0.34) and 57±24% (p =0 .086) in each drug group respectively. Electoretinography (figure) also shows severe reduction in a and b wave amplitudes in all groups except the hypothermia group.


These preliminary results suggest that GABA-ergic drugs fail to protect the retina from injury in ischemia and reperfusion, whereas hypothermia seems to be protective. However, the present results are based on relatively few experiments and need to be verified by more extensive studies.  

Keywords: ischemia • retina • neuroprotection 

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