Prenatal melamine exposure induces impairments of spatial cognition and hippocampal synaptic plasticity in male adolescent rats

Our previous studies showed that chronic melamine exposure could affect hippocampal synaptic plasticity and impair learning and memory on adult rats. In this study, we investigated whether prenatal melamine exposure (PME) induced cognitive deficits and impairment of synaptic plasticity in postnatal offspring. An animal model was produced by melamine exposure throughout gestational period with 400 mg/kg/day, while male offspring rats were employed. Rats' performance in Morris water maze (MWM) was tested to evaluate learning and memory. To examine the variations of paired-pulse facilitation (PPF) and synaptic plasticity, field excitatory postsynaptic potentials (fEPSPs) were recorded in hippocampal CA1 by stimulating Schaffer collaterals path. The result showed that PME probably impaired spatial learning and memory. The fEPSPs amplitudes of LTP were much lower and the PPF ratio was significantly higher in PME group than controls. These data suggested that PME impaired hippocampal synaptic function, which was partly involved in spatial cognition impairments.