Effects of Memantine, an NMDA Antagonist, on Metabolic Syndromes in Female NMRI Mice

Introduction: The brain glutamate neurotransmitter system and its NMDA receptors in the nucleus accumbens play an important role in the incidence of the phenomena of sensitivity and addiction. The present study examined the inhibitory effect of glutamate NMDA receptors in the nucleus accumbens in response to chronic stress. Methods: After the unilateral and bilateral cannula placement in the nucleus accumbens, one group of the animals received different intra-accumbens doses of memantine (0.1, 0.5 and 1 µg/mouse) 5 minutes before receiving the electric shock stress at their soles (using a Communication Box) and the other group received intraperitoneal doses of memantine (0.1, 0.5 and 1mg/kg) 30 minutes before receiving the same shock. Chronic stress increased the animals' plasma corticosterone, food and water intake and weight and reduced their defecation rates and eating latency.  Results: The intraperitoneal administration of memantine increased plasma corticosterone, water intake, fecal weight and eating latency, but had no effect on food intake or weight. The dose and site-dependent intra-accumbens administration of memantine either exacerbated the effects of stress on plasma corticosterone levels and water and food intake, or else had no effect on these parameters. Furthermore, the administration of memantine had no effect on animal’s weight and inhibited the effects of stress on fecal weight and eating latency. Discussion: The inhibition of glutamate NMDA receptors in the nucleus accumbens can inhibit and/or exacerbate the dose and site-dependent effects of chronic stress, with gender playing a significant role in producing this effect

Papaver Rhoeas L. Hydroalcoholic Extract Exacerbates Forced Swimming Test-Induced Depression in Mice

Introduction: Depression is one of the most frequent psychiatric disorders in the world with occurs with higher incidence in women. In the present study, the effect of water-alcoholic extract of Papaver rhoeas L. on forced swimming test (FST) in Swiss-Webster mice were examined. Methods: We used Swiss-Webster mice (20-25 g) to execute FST on them. The plant extract (1, 10, 30, and 100 mg/kg) was injected to the animals 30 minutes before each session. Fluoxetine (20 mg/kg) was used as standard antidepressant drug. In another group of animals, 30 minutes after extract administration, blood samples were taken from retro-orbital sinus for corticosterone assay. Yet in third group, the drugs were injected to the animals and 30 minutes later, their activities were tested in an open field apparatus. Results: Our experiments showed that the extract efficiently reduced FST time both in male and female mice dose-dependently. This effect was comparable with fluoxetine. In addition, corticosterone assay indicated that plasma corticosterone in animals which received extract was higher than those amounts in fluoxetine and saline controls. Moreover, the animals did not show any motor activity deficit in all doses of the extract and fluoxetine compared to saline control. Conclusion: The extract of Papaver rhoeas can reduce immobility time which is comparable to the effect of fluoxetine. Also the effect of the extract is contrary to its effects on plasma corticosterone level and or animals’ activity