Alterations in the Expression of Genes That Encode Subunits of Ionotropic Glutamate Receptors and the Glutamate Transporter in Brain Structures of Rats after Psychogenic Stress

Abstract

We studied modifications in the glutamatergic system of the brain as a factor in the development of post-traumatic stress disorder. An analysis of mRNA production of NMDA (GluN1, GluN2a, and GluN2b) and AMPA (GluA1 and GluA2) glutamate receptors, as well as the EAAT2 glutamate transporter was performed in the brain of rats subjected to stress associated with contact with a predator (a black-tailed python). Studies were performed in 6 or 24 h as well as in 3, 9, and 25 days after stress. The most-pronounced alterations of expression of all studied genes were revealed 25 days after stress. The level of EAAT2 mRNA increased in the ventral hippocampus. The expression of the genes that encode GluA1 and GluA2 subunits of AMPA receptors decreased in the dorsal and increased in the ventral hippocampus. The changes in the expression of the gene that encodes the GluN2b subunit of the NMDA receptor were also region specific. In the ventral hippocampus and medial prefrontal cortex we observed an increase in the expression of GluN2b mRNA, while it decreased in the dorsal hippocampus. The increased expression of the gene that encodes the GluN2a subunit was found in the amygdala. These alterations may be a mechanism of the development of delayed post-stress neurological–psychiatric impairments.