The Effect of Prenatal Stress on the Levels of Nitric Oxide Metabolites in the CNS

Abstract—Nitric oxide has several important functions in the CNS. This neurotransmitter regulates apoptotic processes, differentiation and proliferation of neurons, synaptic activity and plasticity. Stress during the intrauterine period may be a factor influencing the level of NO in various regions of the CNS. The aim of the study was to investigate the levels of NO metabolites in phylogenetically different structures of the CNS in mature male and female rats at various stages estrous cycle, which were subjected to prenatal stress. Twelve pregnant female rats were exposed to stress on gestation days 16–19 for 3 h in the morning. The NO level was estimated in adult 4-month-old offspring of both sexes. In male rats, the decreased levels of NO metabolites were observed in the cerebellum and hypothalamus whereas in the spinal cord, it was increased. In control females, the levels of NO metabolites were higher in all CNS regions compared to males while after prenatal stress, they changed to a lesser extent. Significant differences were revealed in the spinal cord irrespectively of the estrous cycle and in the cerebellum, at the estrus stage. Finally, regardless of sex, the phylogenetically younger cerebral cortex, was the most resilient to prenatal stress whereas the most pronounced changes were revealed in the phylogenetically ancient region of the CNS such as the spinal cord. Taking into account the importance of NO as a key signaling molecule in the CNS, any changes in its level after prenatal stress may have both adaptive and negative consequences for functional condition of the tissue.