June 2013
Volume 54, Issue 15
Free
ARVO Annual Meeting Abstract  |   June 2013
THE EFFECTS OF BRIMONIDINE ON RETINAL SPREADING DEPRESSION
Author Affiliations & Notes
  • Renata Fleming
    Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
  • Vinicius Oliveira
    Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
  • Gabriela Alencar
    Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
  • Nassim Calixto
    Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
  • Sebastiao Cronemberger
    Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
  • Patricia Gardino
    Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
  • Adalmir Dantas
    Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
  • Footnotes
    Commercial Relationships Renata Fleming, None; Vinicius Oliveira, None; Gabriela Alencar, None; Nassim Calixto, None; Sebastiao Cronemberger, None; Patricia Gardino, None; Adalmir Dantas, None
  • Footnotes
    Support None
Investigative Ophthalmology & Visual Science June 2013, Vol.54, 6355. doi:https://doi.org/
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    • Get Citation

      Renata Fleming, Vinicius Oliveira, Gabriela Alencar, Nassim Calixto, Sebastiao Cronemberger, Patricia Gardino, Adalmir Dantas; THE EFFECTS OF BRIMONIDINE ON RETINAL SPREADING DEPRESSION. Invest. Ophthalmol. Vis. Sci. 2013;54(15):6355. doi: https://doi.org/.

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

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Abstract
 
Purpose
 

Brimonidine is a drug used in the management of glaucoma and is the most modern alpha(2) - adrenergic receptor agonist available. α2 - adrenergic receptor agonists have been shown to be neuroprotective in various experimental models, but the molecular and cellular targets leading to these actions are still poorly defined. Brimonidine, a drug used in the management of glaucoma throughout the world, is the most modern alpha2 - adrenergic receptor agonist available. α2 - adrenergic receptor agonists have been shown to be neuroprotective in various experimental models. However, the molecular and cellular targets leading to these actions are still poorly defined. The spreading depression (SD) of electric activity of the retina was initially described by Gouras. SD is a wave of cellular depolarization and has been related to many central nervous diseases. The aim of this study is to investigate the role of brimonidine tartarate (BT) on retinal SD using the chicken retina as a model.

 
Methods
 

Initially we identified the α2 - adrenergic receptor in the retinal chicken tissue using immunoblotting and immunohistochemistry. We then applied electrophysiological methods to investigate the effects of BT over the retinal spread depression in the chicken retina. The slow voltage variation was measured by two electrodes connected to a Grass polygraph while the retina was superfused for 15 minutes with a modified Ringer solution (RS) added to concentrations of BT: 0, 100, 300, 1000, 2200 and 4000 mM. Afterwards, the retina was superfused with RS, twice. We also measured the time interval of the SD passage through the electrodes in order to obtain its velocity.

 
Results
 

Western blotting showed the presence of an α2a- adrenergic receptor in the retinal tissue. Immunohistochemistry demonstrated that α2a - adrenergic receptors are present in Müller cells (Figure 1). The electrophysiological studies demonstrated a significant decrease of the voltage shift at 4000mM (P<0.01) and with the RS immediately after 4000mM (P<0.001), but not with the second RS. The time of SD passage through the electrodes was significantly longer at 2200 mM (P<0.05) and at 4000mM (P<0.001), and with the RS immediately after 4000mM P<0.001, but not with the second RS.

 
Conclusions
 

Our data suggest that BT neuroprotective actions might be mediated by Müller cells and their connections present in different layers of the chicken retina.

  
Keywords: 688 retina • 508 electrophysiology: non-clinical • 603 Muller cells  
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