The role of GluN1 activated nitric oxide synthase in a rat model of post-traumatic stress disorder

Abstract

Objectives: Activation of neuronal nitric oxide synthase (nNOS) and interrelated alterations of calmodulin and ionotropic glutamate receptor (GluN1) levels are unknown in post traumatic stress disorder (PTSD). Materials and Methods: Sprague-Dawley rats of both sexes were exposed to to dirty cat litter, and then placed on an elevated plus maze. An anxiety index was calculated and tissue samples from hippocampus and amygdala were prepered in order to to detect calmodulin, NOS and GluN1 by immunoblotting. Results: The anxiety indices of the traumatized rats were markedly higher than those of the controls (p<0.05). GluN1 and calmodulin levels were decreased in the dorsal hippocampus and amygdaloid complex of the traumatized rats. NOS expression increased significantly in both the amygdaloid complex and dorsal hippocampus where the increase was statistically more prominent in the amygdaloid complex (p<0.001) than in the dorsal hippocampus of the traumatized rats (p<0.05). Conclusion: Predator exposure in rats causes long-lasting anxiogenic effects associated with increases in NOS and decreases in GluN1 expressions in brain areas related to PTSD symptoms and excitotoxicity. The results suggest that excitotoxicity occurs through other mechanisms rather than GluN1 receptors.