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Merck

[Changes of synaptoarchitecture of the retina after the light-induced damage and their correction by plant antioxidants].

Morfologiia (Saint Petersburg, Russia) (2008-12-17)
S V Logvinov, E Iu Varakuta, A A Zhdankina, A V Potapov, M B Plotnikov
ABSTRAKT

The changes of interneuronal contacts in the internal reticular layer of albino rat retina were studied 7 and 30 days after the exposure to high intensity light (6000 Lux for 6 h). In osmicated preparations, the "light" type of synapse destruction was predominant 7 days after the light-induced damage. Using the contrasting by phosphotungstic acid, paramembrane structures of the system of subsynaptic units--dense projections and postsynaptic condensations of synapses--were studied. It was found that the exposure to high intensity light resulted in the destructive changes of synapses and the decrease of their numeral density at the expense of the actively functioning symmetric contacts. 30 days after the light-induced damage, the numeral density of symmetric contacts was significantly increased, while the content of symmetric mature synapses was decreased. Course administration of ascovertine and carovertine before and after the exposure to light was found to have a differential effect on limiting the destruction of the synapses and on the activation of the repair mechanisms which are realized due to the hypertrophy and neosynaptogenesis. The highest effect was found after carovertine administration.