Neurochemical and behavioural effects of acute and chronic memantine administration in rats: Further support for NMDA as a new pharmacological target for the treatment of depression?

A growing body of evidence has pointed to the NMDA receptor antagonists as a potential therapeutic target for the treatment of major depression. The present study was aimed to evaluate behavioural and molecular effects of the acute and chronic treatment with memantine and imipramine in rats. To this aim, rats were acutely or chronically for 14 days once a day treated with memantine (5, 10 and 20 mg/kg) and imipramine (10, 20 and 30 mg/kg) and then subjected to the forced swimming and open-field tests. The acute treatment with memantine at all doses and imipramine at doses (20 and 30 mg/kg) reduced immobility time of rats compared to the saline group (p < 0.05), without affecting spontaneous locomotor activity and chronic treatment with memantine and imipramine, at all doses tested, reduced immobility time of rats compared to the saline group (p < 0.05), without affecting spontaneous locomotor activity. Brain-derived neurotrophic factor (BDNF) hippocampal levels were assessed in imipramine- and memantine-treated rats by ELISA sandwich assay. Interesting enough, acute administration, but not chronic administration of memantine at higher dose (20 mg/kg) increased BDNF protein levels in the rat hippocampus (p < 0.05). Finally, these findings further support the hypothesis that NMDA receptor could be a new pharmacological target for the treatment of depression.