Effects of chronic memantine treatment on hippocampal extracellular glutamate and GABA levels during spatial alternation testing

These experiments examined the release of glutamate (Glu) and GABA in the hippocampus of memantine (2,5mg/kg, i.p. for four weeks) or saline treated rats prior to, during, and after spontaneous alternation test. Glu and GABA release during the 10 min samples taken at the time of the behavioral testing of memantine or saline treated animals were not different from those seen immediately before and after testing. Similarly, the alternation scores were not significantly different between groups. We found increase in KCl-stimulated glutamate and GABA release in the hippocampus of memantine treated rat compared to the saline treated rat. This difference in KCl response between memantine treated and control rat was statistically significant (p<0,05). Our evaluation of memantine reveals that changes in KCl-stimulated Glu and GABA release after chronic memantine treatment did not affect working memory in adult rats assessed in spontaneous alternation task.