Effects of enriched environment in spatial learning and memory of immature rats submitted to early undernourish and seizures

Undernourishment and recurrent seizures early in life impair Long-Term Potentiation and alter NMDAR and AMPAR expression in rat hippocampus

Undernourishment is a global issue, especially in developing countries, affecting newborns and children in a vulnerable period of brain development. Previous studies of undernourishment models suggested a relationship between undernourishment and epilepsy. The exposure to both undernourishment and recurrent seizures early in life appears to have detrimental effects on the developing brain. This study aims to investigate the neurobiological consequences of undernourishment and recurrent seizures exposure early in life, investigating Long-Term Potentiation (LTP) induction and gene expression of NMDA receptor subunits in the hippocampus during adulthood (P60). Animals were exposed to maternal deprivation protocol from P2 to P15 to control food intake in rat pups and Flurothyl-induced seizures from P7 to P10. Electrophysiological records of hippocampal slices were recorded and gene expression of NR1A, NR2A, NR2B, NR2C, NR2D and BDNF were investigated. Animals exposed to undernourishment or recurrent seizures failed to promote LTP after stimulation. Furthermore, seizure exposure early in life led to increased expression of hippocampal NR1A, NR2A, NR2B, NR2C and NR2D when compared to controls. Interestingly, when animals were exposed to undernourishment paradigm early in life, this upregulation of NDMA subunits was absent. In conclusion, our study showed impaired LTP after undernourishment and recurrent seizures early in life, together with differential expression of NDMA expression in the hippocampus during adulthood.