Role of NMDA glutamate receptors within the amygdale in inhibition of the metabolic effects of acute stress in male mice

Amygdala is known as one of the most important regions of the brain in response to stressful stimuli. In the present study, the role of N-methyl-D-aspartate (NMDA) glutamate receptors within the amygdala in inhibition of the metabolic effects of acute stress in male mice was investigated. In this experimental study, bilateral or unilateral amygdala cannulation was performed stereotaxically. After a seven-day recovery period, the animals (11 groups of seven each) received different doses of memantine (1, 0.5, and 0.1 µg/mouse) five min before the stress induction. Food and water intake, delay to eating time, and fecal material as stress metabolic parameters were measured. Stress had no effect on water intake, but reduced food intake and, increased delay to eating time and fecal materials. Moreover, injection of memantine to the right or left side of amygdala decreased water intake, and injection at a dose of 0.1 µg to the left amygdala inhibited the effect of stress and increased the food intake. Also, an injection of memantine in the left or right amygdala decreased delay to eating time and decreased fecal material at 1 and 0.5 µg/mouse doses that the right of the core had the greatest inhibitory effect in this regard. It seems that the amygdala glutamate system, in particular its NMDA receptors, may have a significant effect on regulating the stress responses, which this effect is a side-dependent phenomenon.