Effect of prenatal stress on density of NMDA receptors in rat brain

N-methyl-d-aspartate (NMDA) receptors are important excitatory receptors which contribute to manybrain functions. Altered NMDA receptor levels cause maldevelopment of corticostriatal and corticolimbicpathways, which is a neurobiological predisposing factor for development of epilepsy, schizophrenia andother idiopathic psychotic disorders. It was hypothesized that prenatal stress could play a role in patho-physiology of these disorders by affecting expression of the receptors through releasing corticosterone.Sixty-eight virgin female Wistar rats were selected and mated with male rats with the same genotype.Then, the pregnant rats were subjected to restraint or predator stress on 15th, 16th and 17th gestationdays. Prenatal stress consisted of restraint or predator stresses of the dams under normal room condi-tions. After parturition, the pups were studied in terms of density of NMDA receptors in brain at differenttime points. Meanwhile, blood sample was obtained and corticosterone blood level (CBL) was measured.The pups were then compared with the pups born to unstressed dams. Stress induced significant rise inCBL and NMDA receptors in brain of the offspring. CBL was significantly higher among the stressed ratscompared to the control ones; there was significant difference between the two stresses and betweenthe two sexes. The male pups were affected more severely. Stressful events during gestation had impor-tant effects on NMDA receptors of the offspring. It can be concluded that stress-induced elevation ofNMDA receptors and corticosterone might mediate altered susceptibility to epilepsy and decrease abilityof learning and memory and other stress-induced neurologic disorders