Document Detail


Correlating retinal function and amino acid immunocytochemistry following post-mortem ischemia.
MedLine Citation:
PMID:  12873442     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
We wanted to determine the characteristics associated with electrophysiological and neurochemical changes secondary to ischemic insult as well as correlate these electrophysiological and neurochemical changes. A Ganzfeld source was used to elicit electroretinograms in anesthetized adult Sprague-Dawley rats. Following baseline recordings, one eye was removed for control quantitative amino acid immunocytochemistry, and ischemic insult was induced by cervical dislocation. Following the induction of ischemia, a single electroretinogram signal was collected at 1, 2, 4, 6, 8, 16, 32 or 64 min, after which the eye was removed for immunocytochemistry. The post-receptoral b-wave was undetectable after 1 min post-ischemia, whereas phototransduction declined more gradually and persisted for up to 16 min post-mortem. Both phototransduction saturated amplitude and sensitivity decayed with a similar time course (tc=3.06 (2.73, 3.48) versus 3.29 (2.61, 4.62)min). Significant elevation of amino acid neurotransmitter levels was not observed until 6 min post-mortem. Between 8 and 16 min post-ischemia, glutamate and GABA were significantly accumulated in neurons and Müller cells (p<0.05). Beyond 16 min, the neurotransmitter elevation in neurons and Müller cells was relatively attenuated. Aspartate immunoreactivity was significantly elevated at 4 and 6 min post-ischemia in neurons, prior to a change in any other amino acid. Moreover, of the amino acids assessed the post-ischemic change in aspartate immunoreactivity showed the best correlation with phototransduction decay (r2=0.68). Our findings show that complete impairment of phototransduction coincides with the accumulation of amino acid neurotransmitter. The correlation of aspartate immunoreactivity and phototransduction provides evidence of heightened glutamate oxidation during ischemic insult.
Authors:
B V Bui; A J Vingrys; Michael Kalloniatis
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Experimental eye research     Volume:  77     ISSN:  0014-4835     ISO Abbreviation:  Exp. Eye Res.     Publication Date:  2003 Aug 
Date Detail:
Created Date:  2003-07-22     Completed Date:  2003-08-19     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  0370707     Medline TA:  Exp Eye Res     Country:  England    
Other Details:
Languages:  eng     Pagination:  125-36     Citation Subset:  IM    
Affiliation:
Department of Optometry and Vision Sciences, University of Melbourne, Parkville 3010, Victoria, Australia.
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MeSH Terms
Descriptor/Qualifier:
Animals
Aspartic Acid / metabolism
Electroretinography
Glutamic Acid / metabolism
Glycine / metabolism
Immunohistochemistry / methods
Ischemia / metabolism,  physiopathology*
Rats
Rats, Sprague-Dawley
Retinal Vessels / physiology*
Time Factors
Vision, Ocular / physiology
gamma-Aminobutyric Acid / metabolism
Chemical
Reg. No./Substance:
56-12-2/gamma-Aminobutyric Acid; 56-40-6/Glycine; 56-84-8/Aspartic Acid; 56-86-0/Glutamic Acid
Comments/Corrections
Erratum In:
Exp Eye Res. 2005 Jan;80(1):147   [PMID:  15652535 ]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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