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Abstract
Two different monolayer culture preparations were used to investigate the effects of glutamate and kainate on retinal cell proliferation. Glial monolayer cultures were produced from 8-day-old chick embryo neural retina. Glial monolayers were exposed to glutamate (5 mM) or kainate (0.4 mM) at either 3 or 5 days in vitro. It was found that exposure to glutamate at 3 days in vitro significantly reduced the number of glia present at 6 days, but a day 5 exposure or exposure to kainate did not significantly affect the number of glia. This glutamate-induced decrease in cell number was seen even though thymidine kinase (EC 2.7.75) and thymidylate synthetase (EC 2.1.1-) activities were higher in treated cultures. Neuroblast monolayer cultures were produced from 6-day-old chick embryo neural retina. These cultures also were exposed to glutamate (5 mM) or kainate (0.4 mM) Glutamate, but not kainate treated cultures, showed a decrease in neuroblast survival and proliferation compared with controls. Thus, at the concentrations tested, glutamate appears to be a general retinal toxin, while the survival of immature neurons or glia is not affected by kainate.